La multiplication : corrigés des exercices de maths en 6ème.

Exercice 1 : poser et effectuer les multiplications
$a.\,\quad\,68%2C7\,\times \,39$

$68%2C7\,\times \,39\,=\,68%2C7\,\times \,(40\,-\,1)\,=\,68%2C7\,\times \,40\,-\,68%2C7\,\times \,1$

$68%2C7\,\times \,40\,=\,68%2C7\,\times \,4\,\times \,10\,=\,274%2C8\,\times \,10\,=\,2748$

$68%2C7\,\times \,1\,=\,68%2C7$

$68%2C7\,\times \,39\,=\,2748\,-\,68%2C7\,=\,2679%2C3$

$b.\,\quad\,123\,\times \,6%2C3$

$123\,\times \,6%2C3\,=\,123\,\times \,(6\,%2B\,0%2C3)\,=\,123\,\times \,6\,%2B\,123\,\times \,0%2C3$

$123\,\times \,6\,=\,738$

$123\,\times \,0%2C3\,=\,123\,\times \,\frac{3}{10}\,=\,\frac{123\,\times \,3}{10}\,=\,\frac{369}{10}\,=\,36%2C9$

$123\,\times \,6%2C3\,=\,738\,%2B\,36%2C9\,=\,774%2C9$

$c.\,\quad\,1%2C3\,\times \,0%2C7$

$1%2C3\,\times \,0%2C7\,=\,\frac{13}{10}\,\times \,\frac{7}{10}\,=\,\frac{13\,\times \,7}{100}\,=\,\frac{91}{100}\,=\,0%2C91$

$d.\,\quad\,54%2C6\,\times \,8%2C25$

$54%2C6\,\times \,8%2C25\,=\,54%2C6\,\times \,(8\,%2B\,0%2C25)\,=\,54%2C6\,\times \,8\,%2B\,54%2C6\,\times \,0%2C25$

$54%2C6\,\times \,8\,=\,436%2C8$

$54%2C6\,\times \,0%2C25\,=\,54%2C6\,\times \,\frac{1}{4}\,=\,\frac{54%2C6}{4}\,=\,13%2C65$

$54%2C6\,\times \,8%2C25\,=\,436%2C8\,%2B\,13%2C65\,=\,450%2C45$

Exercice 2 : calculer mentalement des produits
a. $4%2C357\,\times \,100\,=\,435%2C7$

b. $89%2C7\,\times \,1\%2C000\,=\,89\%2C700$

c. $0%2C043\,\times \,10\,=\,0%2C43$

d. $0%2C28\,\times \,1\%2C000\,=\,280$

e. $39\,\times \,100\,=\,3\%2C900$

f. $0%2C48\,\times \,10\,=\,4%2C8$

g. $354\,\times \,10\,=\,3\%2C540$

h. $0%2C03\,\times \,10\%2C000\,=\,300$

Exercice 3 : pacer la virgule dans des produits

a. $12%2C8\,\times \,5%2C3\,=\,67%2C84$

b. $28%2C7\,\times \,1%2C04\,=\,29%2C848$

c. $0%2C15\,\times \,6%2C3\,=\,0%2C945$

d. $0%2C008\,\times \,543%2C9\,=\,4%2C3512$

e. $0%2C235\,\times \,0%2C132\,=\,0%2C03102$

Exercice 4 : effectuer les multiplications
a.
$93%2C76\,\times \,5\,=\,468%2C80$

b.
$356%2C1\,\times \,14\,=\,4985%2C4$

c.
$14%2C9\,\times \,0%2C8\,=\,11%2C92$

Exercice 5 : calculer des produits
a.
$52\,\times \,0.8\,=\,52\,\times \,\frac{8}{10}\,=\,52\,\times \,0.8\,=\,41.6$

b.
$1.7\,\times \,0.09\,=\,1.7\,\times \,\frac{9}{100}\,=\,1.7\,\times \,0.09\,=\,0.153$

c.
$0.41\,\times \,5\,=\,0.41\,\times \,5\,=\,2.05$

d.
$1.3\,\times \,7.5\,=\,1.3\,\times \,7.5\,=\,9.75$

e.
$0.17\,\times \,2.8\,=\,0.17\,\times \,2.8\,=\,0.476$

f.
$10.5\,\times \,3.2\,=\,10.5\,\times \,3.2\,=\,33.6$

Exercice 6 : la multiplication
$3%2C4\,\times \,100\,=\,340$

$3%2C47\,\times \,10\,=\,34%2C7$

$0%2C58\,\times \,0%2C1\,=\,0%2C058$

$0%2C02\,\times \,1000\,=\,20$

$5923\,\times \,0%2C01\,=\,59%2C23$

$34%2C78\,\times \,0%2C01\,=\,0%2C3478$

$564%2C8\,\times \,100\,=\,56480$

$0%2C28\,\times \,1000\,=\,280$

$0%2C002\,\times \,0%2C1\,=\,0%2C0002$

$10\,\times \,0%2C01\,=\,0%2C1$

Exercice 7 : sans poser l’opération

$10%2C3\,\times \,7%2C5$ : Le résultat le plus proche est . On entoure donc la case C.

$11%2C6\,\times \,29%2C8$ : Le résultat le plus proche est . On entoure donc la case D.

$346\,\times \,0%2C97$ : Le résultat le plus proche est . On entoure donc la case C.

$1%2C03\,\times \,698%2C4$ : Le résultat le plus proche est . On entoure donc la case B.

$2%2C5\,\times \,4%2C4$ : Le résultat le plus proche est . On entoure donc la case B.

Exercice 8 : multiplication et calculs astucieux

[a.] $5\,\times \,33\,\times \,2$
$5\,\times \,2\,\times \,33\,=\,10\,\times \,33\,=\,330$

[b.] $50\,\times \,33\,\times \,2\,\times \,30$
$50\,\times \,2\,\times \,30\,\times \,33\,=\,100\,\times \,30\,\times \,33\,=\,3000\,\times \,33\,=\,99000$

[c.] $4\,\times \,1725\,\times \,250\,\times \,10$
$4\,\times \,250\,\times \,1725\,\times \,10\,=\,1000\,\times \,1725\,\times \,10\,=\,1000\,\times \,17250\,=\,17250000$

[d.] $19398\,\times \,22119\,\times \,0\,\times \,56$
(Tout nombre multiplié par 0 donne 0)

[e.] $188\,\times \,8\,\times \,125$
$8\,\times \,125\,=\,1000\,\to\,188\,\times \,1000\,=\,188000$

[f.] $99\,\times \,500\,\times \,2$
$500\,\times \,2\,=\,1000\,\to\,99\,\times \,1000\,=\,99000$

Exercice 9 : déterminer les résultats des calculs
Sachant que $65\,\times \,132\,=\,8580$ , nous pouvons utiliser cette information pour déterminer les résultats des calculs suivants :

a. $6{%2C}5\,\times \,13{%2C}2$

$6{%2C}5\,\times \,13{%2C}2\,=\,\frac{65}{10}\,\times \,\frac{132}{10}\,=\,\frac{65\,\times \,132}{100}\,=\,\frac{8580}{100}\,=\,85{%2C}8$

b. $650\,\times \,132$

$650\,\times \,132\,=\,(65\,\times \,10)\,\times \,132\,=\,65\,\times \,(10\,\times \,132)\,=\,65\,\times \,1320\,=\,8580\,\times \,10\,=\,85800$

c. $0{%2C}65\,\times \,0{%2C}132$

$0{%2C}65\,\times \,0{%2C}132\,=\,\frac{65}{100}\,\times \,\frac{132}{1000}\,=\,\frac{65\,\times \,132}{100\,\times \,1000}\,=\,\frac{8580}{100000}\,=\,0{%2C}0858$

d. $0{%2C}065\,\times \,1320$

$0{%2C}065\,\times \,1320\,=\,\frac{65}{1000}\,\times \,1320\,=\,\frac{65\,\times \,1320}{1000}\,=\,\frac{65\,\times \,(132\,\times \,10)}{1000}\,=\,\frac{65\,\times \,132\,\times \,10}{1000}\,=\,\frac{8580\,\times \,10}{1000}\,=\,\frac{85800}{1000}\,=\,85{%2C}8$

Exercice 10 : multiplications de décimaux

1. $91%2C9\,\times \,0%2C04\,=\,3%2C676$
2. $178\,\times \,0%2C03\,=\,5%2C34$
3. $0%2C906\,\times \,7%2C5\,=\,6%2C795$
4. $9%2C49\,\times \,7%2C2\,=\,68%2C328$
5. $41%2C1\,\times \,0%2C86\,=\,35%2C346$
6. $680\,\times \,0%2C48\,=\,326%2C4$
7. $0%2C403\,\times \,0%2C67\,=\,0%2C27001$
8. $4%2C76\,\times \,0%2C03\,=\,0%2C1428$
9. $509\,\times \,0%2C01\,=\,5%2C09$
10. $74%2C5\,\times \,94\,=\,7003$
11. $698\,\times \,3%2C3\,=\,2303%2C4$
12. $0%2C324\,\times \,0%2C27\,=\,0%2C08748$

Exercice 11 : multiplications et calculs de produits
$45%2C87\,\times \,23$
$45%2C87\,\times \,23\,=\,1055%2C01$

$15%2C4\,\times \,10$
$15%2C4\,\times \,10\,=\,154$

$458\,\times \,0%2C003$
$458\,\times \,0%2C003\,=\,1%2C374$

$154\,\times \,57%2C555$
$154\,\times \,57%2C555\,=\,8\,861%2C37$

$456\,\times \,1%2C001$
$456\,\times \,1%2C001\,=\,456%2C456$

$4567\,\times \,1%2C3$
$4567\,\times \,1%2C3\,=\,5937%2C1$

Exercice 12 : calculer le résultat
$\begin{array}{r}%0D%0A961\,\\%0D%0A\times \,78\,\\%0D%0A\hline%0D%0A\begin{array}{r}%0D%0A7688\,\\%0D%0A%2B74880\,\\%0D%0A\end{array}\,\\%0D%0A\hline%0D%0A74958\,\\%0D%0A\end{array}$

$\begin{array}{r}%0D%0A508\,\\%0D%0A\times \,79\,\\%0D%0A\hline%0D%0A\begin{array}{r}%0D%0A4064\,\\%0D%0A%2B35560\,\\%0D%0A\end{array}\,\\%0D%0A\hline%0D%0A40132\,\\%0D%0A\end{array}$

$\begin{array}{r}%0D%0A340\,\\%0D%0A\times \,74\,\\%0D%0A\hline%0D%0A\begin{array}{r}%0D%0A1360\,\\%0D%0A%2B23800\,\\%0D%0A\end{array}\,\\%0D%0A\hline%0D%0A25160\,\\%0D%0A\end{array}$

Exercice 13 : multiplications posées
$1.\,Calcul\,%3A\quad\,274\,\times \,52$

$\begin{align%2A}%0D%0A274\,\times \,52\,%26=\,274\,\times \,(50\,%2B\,2)\,\\%0D%0A%26=\,274\,\times \,50\,%2B\,274\,\times \,2\,\\%0D%0A%26=\,13700\,%2B\,548\,\\%0D%0A%26=\,14248%0D%0A\end{align%2A}$

$Resultat\,%3A\,\quad\,274\,\times \,52\,=\,14248$

$2.\,Calcul\,%3A\quad\,636\,\times \,85$

$\begin{align%2A}%0D%0A636\,\times \,85\,%26=\,636\,\times \,(80\,%2B\,5)\,\\%0D%0A%26=\,636\,\times \,80\,%2B\,636\,\times \,5\,\\%0D%0A%26=\,50880\,%2B\,3180\,\\%0D%0A%26=\,54060%0D%0A\end{align%2A}$

$Resultat\,%3A\,\quad\,636\,\times \,85\,=\,54060$

$3.\,Calcul\,%3A\quad\,377\,\times \,61$

$\begin{align%2A}%0D%0A377\,\times \,61\,%26=\,377\,\times \,(60\,%2B\,1)\,\\%0D%0A%26=\,377\,\times \,60\,%2B\,377\,\times \,1\,\\%0D%0A%26=\,22620\,%2B\,377\,\\%0D%0A%26=\,22997%0D%0A\end{align%2A}$

$Resultat\,%3A\,\quad\,377\,\times \,61\,=\,22997$

Exercice 14 : poser des multiplications en colonne

$764\times \,\\,70\,=53480$
$710\,\times \,\\,19\,=6390$

$348\times \%2C91=31\%2C668$

Exercice 15 : calculer les produits suivants

1. $487\,\times \,84$ = 40908

2. $248\,\times \,42\,=10416$

3. $909\,\times \,59=53631$

Exercice 16 : donner le résultat
$\begin{array}{cccc}%0D%0A%26\,\phantom{0}\,%26\,4\,%26\,2\,\\%0D%0A%26\,\times \,%26\,5\,%26\,1\,\\%0D%0A\hline%0D%0A%26\,\phantom{0}\,%26\,4\,%26\,2\,\\%0D%0A%2B\,%26\,2\,%26\,1\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,1\,%26\,4\,%26\,2\,\\%0D%0A\end{array}$

$42\,\times \,51\,=\,2142$

$\begin{array}{cccc}%0D%0A%26\,3\,%26\,4\,%26\,2\,\\%0D%0A%26\,\times \,%26\,1\,%26\,4\,\\%0D%0A\hline%0D%0A%26\,\phantom{0}\,%26\,3\,%26\,4\,%26\,2\,\\%0D%0A%2B\,%26\,1\,%26\,3\,%26\,6\,%26\,8\,\\%0D%0A\hline%0D%0A%26\,4\,%26\,7\,%26\,8\,%26\,8\,\\%0D%0A\end{array}$

$342\,\times \,14\,=\,4788$

$\begin{array}{cccc}%0D%0A%26\,4\,%26\,3\,%26\,5\,\\%0D%0A%26\,\times \,%26\,2\,%26\,8\,\\%0D%0A\hline%0D%0A%26\,\phantom{0}\,%26\,3\,%26\,4\,%26\,8\,%26\,0\,\\%0D%0A%2B\,%26\,8\,%26\,7\,%26\,0\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,2\,%26\,1\,%26\,8\,%26\,0\,\\%0D%0A\end{array}$

$435\,\times \,28\,=\,12180$

Exercice 17 : poser ces multiplications et donner le résultat
$\begin{array}{c%7Cc%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A561\,%26\,5\,%26\,6\,%26\,1\,%26\,\\%0D%0A\times \,%26\,%26\,1\,%26\,2\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,1\,%26\,1\,2\,%26\,2\,\\%0D%0A%2B\,%26\,5\,%26\,6\,%26\,1\,0\,%26\,8\,\\%0D%0A\hline%0D%0A%26\,6\,%26\,7\,%26\,3\,%26\,2\,\\%0D%0A\end{array}%0D%0A\\%0D%0A561\,\times \,12\,=\,6732$

$\begin{array}{c%7Cc%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A69\,%26\,6\,%26\,9\,%26\,\\%0D%0A\times \,%26\,%26\,4\,%26\,8\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,5\,%26\,5\,2\,%26\,\\%0D%0A%2B\,%26\,3\,%26\,4\,%26\,5\,%26\,2\,\\%0D%0A\hline%0D%0A%26\,3\,%26\,3\,%26\,1\,%26\,2\,\\%0D%0A\end{array}%0D%0A\\%0D%0A69\,\times \,48\,=\,3312$

$\begin{array}{c%7Cc%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A346\,%26\,3\,%26\,4\,%26\,6\,%26\,\\%0D%0A\times \,%26\,%26\,7\,%26\,4\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,1\,%26\,3\,8\,%26\,4\,\\%0D%0A%2B\,%26\,2\,%26\,4\,%26\,2\,2\,0\,%26\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,5\,%26\,6\,%26\,0\,4\,\\%0D%0A\end{array}%0D%0A\\%0D%0A346\,\times \,74\,=\,25604$

Exercice 18 : poser des multiplications en colonne
123 × 12 :
$\begin{array}{c%7Cc%7Cc}%0D%0A%26\,1\,%26\,2\,%26\,3\,\\%0D%0A\times \,%26\,%26\,1\,%26\,2\,\\%0D%0A\hline%0D%0A%26\,%26\,2\,%26\,4\,%26\,6\,\\%0D%0A%2B\,%26\,1\,%26\,2\,%26\,3\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,4\,%26\,7\,%26\,6\,\\%0D%0A\end{array}$

Donc, 123 × 12 = 1476.

426 × 46 :
$\begin{array}{c%7Cc%7Cc%7Cc}%0D%0A%26\,4\,%26\,2\,%26\,6\,\\%0D%0A\times \,%26\,%26\,4\,%26\,6\,\\%0D%0A\hline%0D%0A%26\,%26\,2\,%26\,5\,%26\,6\,\\%0D%0A%2B\,%26\,1\,%26\,7\,%26\,0\,%26\,4\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,9\,%26\,5\,%26\,9\,%26\,6\,\\%0D%0A\end{array}$

Donc, 426 × 46 = 19596.

846 × 34 :
$\begin{array}{c%7Cc%7Cc%7Cc}%0D%0A%26\,8\,%26\,4\,%26\,6\,\\%0D%0A\times \,%26\,%26\,3\,%26\,4\,\\%0D%0A\hline%0D%0A%26\,%26\,1\,%26\,6\,%26\,9\,%26\,2\,%26\,0\,\\%0D%0A%2B\,%26\,2\,%26\,5\,%26\,3\,%26\,8\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,8\,%26\,7\,%26\,6\,%26\,4\,\\%0D%0A\end{array}$

Donc, 846 × 34 = 28764.

Exercice 19 : écrire le résultat de ces produits

1. La réponse est donc $45\,\times \,63\,=\,2835$ .

2. La réponse est donc $432\,\times \,28\,=\,12096$ .

3. La réponse est donc $208\,\times \,28\,=\,5824$ .

Exercice 20 : poser ces opérations en colonne
$\begin{array}{cccc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A%26\,%26\,3\,%26\,9\,%26\,4\,\\%0D%0A\times \,%26\,%26\,%26\,6\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,3\,%26\,6\,%26\,4\,%26\,0\,\\%0D%0A%2B\,%26\,0\,%26\,0\,%26\,0\,%26\,\%2C\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,3\,%26\,6\,%26\,4\,%26\,0%0D%0A\end{array}$

$\begin{array}{cccc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,8\,%26\,1\,\\%0D%0A\times \,%26\,%26\,%26\,6\,%26\,4\,\\%0D%0A\hline%0D%0A%26\,%26\,4\,%26\,8\,%26\,6\,%26\,4\,\\%0D%0A%2B\,%26\,%26\,3\,%26\,2\,%26\,4\,%26\,0\,\\%0D%0A\hline%0D%0A%26\,5\,%26\,1\,%26\,8\,%26\,4%0D%0A\end{array}$

$\begin{array}{cccc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,1\,%26\,8\,\\%0D%0A\times \,%26\,%26\,%26\,9\,%26\,6\,\\%0D%0A\hline%0D%0A%26\,%26\,7\,%26\,2\,%26\,8\,%26\,8\,\\%0D%0A%2B\,%26\,%26\,1\,%26\,6\,%26\,2\,%26\,8\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,7\,%26\,2\,%26\,8%0D%0A\end{array}$

Voir Corrigés 11 à 20 ...

Exercice 21 : trouver le chiffre des milliers
$\begin{array}{lllll}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,%26\,1\,%26\,6\,%26\,2\,\\%0D%0A\times \,%26\,1\,%26\,5\,%26\,7\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,1\,%26\,1\,%26\,3\,%26\,4\,\\%0D%0A%26\,%26\,8\,%26\,1\,%26\,0\,%26\,\\%0D%0A%2B\,%26\,1\,%26\,6\,%26\,2\,%26\,\\%0D%0A\hline%0D%0A%26\,2\,%26\,5\,%26\,4\,%26\,3\,%26\,4\,\\%0D%0A\end{array}$

$162\,\times \,157\,=\,25434$

$\begin{array}{lllll}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,%26\,2\,%26\,1\,%26\,9\,\\%0D%0A\times \,%26\,7\,%26\,5\,%26\,4\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,8\,%26\,7\,%26\,6\,\\%0D%0A%26\,1\,%26\,0\,%26\,9\,%26\,5\,%26\,\\%0D%0A%2B\,%26\,1\,%26\,5\,%26\,3\,%26\,3\,%26\,2\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,6\,%26\,5\,%26\,1\,%26\,6\,\\%0D%0A\end{array}$

$219\,\times \,754\,=\,165126$

$\begin{array}{lllll}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,%26\,8\,%26\,4\,%26\,7\,\\%0D%0A\times \,%26\,1\,%26\,2\,%26\,4\,%26\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,3\,%26\,3\,%26\,8\,%26\,8\,\\%0D%0A%26\,%26\,6\,%26\,7\,%26\,7\,%26\,6\,%26\,\\%0D%0A%2B\,%26\,1\,%26\,6\,%26\,9\,%26\,4\,%26\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,0\,%26\,5\,%26\,0\,%26\,2\,%26\,8\,\\%0D%0A\end{array}$

$847\,\times \,124\,=\,105028$

Exercice 22 : produit et résultat à déterminer

Pour le calcul $741\,\times \,162$ :

$\begin{array}{c%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,7\,%26\,4\,%26\,1\,\\%0D%0A\times \,%26\,1\,%26\,6\,%26\,2\,\\\,\hline%0D%0A%26\,%26\,%26\,%26\,1482\,\\%0D%0A%26\,%26\,%26\,4410\,%26\,\\%0D%0A%26\,%26\,74100\,%26\,%26\,\\\,\hline%0D%0A%26\,%26\,119\,%26\,982\,\\%0D%0A\end{array}$
Résultat: $741\,\times \,162\,=\,120042$ .

Pour le calcul $467\,\times \,112$ :

$\begin{array}{c%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,4\,%26\,6\,%26\,7\,\\%0D%0A\times \,%26\,1\,%26\,1\,%26\,2\,\\\,\hline%0D%0A%26\,%26\,%26\,934\,\\%0D%0A%26\,%26\,%26\,4670\,\\%0D%0A%26\,%26\,46700\,%26\,\\\,\hline%0D%0A%26\,%26\,50204\,%26\,\\%0D%0A\end{array}$
Résultat: $467\,\times \,112\,=\,52304$ .

Pour le calcul $321\,\times \,124$ :

$\begin{array}{c%7Cc%7Cc%7Cc}%0D%0A%26\,m\,%26\,c\,%26\,d\,%26\,u\,\\%0D%0A%26\,3\,%26\,2\,%26\,1\,\\%0D%0A\times \,%26\,1\,%26\,2\,%26\,4\,\\\,\hline%0D%0A%26\,%26\,%26\,%26\,1284\,\\%0D%0A%26\,%26\,6420\,%26\,%26\,\\%0D%0A%26\,%26\,32100\,%26\,%26\,\\\,\hline%0D%0A%26\,%26\,39804\,%26\,\\%0D%0A\end{array}$
Résultat: $321\,\times \,124\,=\,39804$ .

Exercice 23 : compléter les lignes
$\begin{array}{c\,c\,c\,c}%0D%0A%26\,%26\,5\,%26\,5\,%26\,2\,\\%0D%0A\times \,%26\,%26\,2\,%26\,6\,%26\,2\,\\%0D%0A\hline%0D%0A%26\,1\,%26\,1\,%26\,0\,%26\,4\,\\%0D%0A%2B\,%26\,3\,%26\,3\,%26\,1\,%26\,2\,%26\,\\%0D%0A\hline%0D%0A=\,%26\,1\,%26\,4\,%26\,4\,%26\,5\,%26\,8\,%26\,2\,\\%0D%0A\end{array}$

144584

$\begin{array}{c\,c\,c\,c}%0D%0A%26\,%26\,1\,%26\,5\,%26\,4\,\\%0D%0A\times \,%26\,%26\,1\,%26\,3\,%26\,2\,\\%0D%0A\hline%0D%0A%26\,%26\,1\,%26\,2\,%26\,3\,%26\,2\,\\%0D%0A%2B\,%26\,%26\,1\,%26\,8\,%26\,4\,%26\,8\,%26\,\\%0D%0A\hline%0D%0A=\,%26\,1\,%26\,4\,%26\,5\,%26\,3\,%26\,2\,%26\,8\,\\%0D%0A\end{array}$

20328

$\begin{array}{c\,c\,c\,c}%0D%0A%26\,%26\,6\,%26\,5\,%26\,5\,\\%0D%0A\times \,%26\,%26\,1\,%26\,2\,%26\,4\,\\%0D%0A\hline%0D%0A%26\,%26\,%26\,2\,%26\,6\,%26\,2\,\\%0D%0A%2B\,%26\,4\,%26\,4\,%26\,6\,%26\,2\,%26\,0\,%26\,\\%0D%0A\hline%0D%0A=\,%26\,8\,%26\,1\,%26\,2\,%26\,2\,%26\,4\,%26\,0\,\\%0D%0A\end{array}$