2nd Grade Subtracting Within 100 Worksheet Solutions (PDF)
This subtract within 100 answers for 2nd Grade covers subtracting within 100 (Common Core 2.NBT.B.5, 2.NBT.B.9), with a free PDF to print.
Grade 2 · Common Core State Standards: 2.NBT.B.5, 2.NBT.B.9
Subtract within 100 answers: exercises 1 to 10
Exercise 1 – Subtract tens
Think of 68 as 6 tens and 8 ones. Take away 3 tens: 6 tens – 3 tens = 3 tens. The 8 ones stay.
\(68 – 30 = 38\)
\(38\)
Exercise 2 – No trade needed
Write 79 as 7 tens, 9 ones.
Ones: \(9 – 5 = 4\).
Tens: \(7 – 3 = 4\).
So \(79 – 35 = 44\).
\(44\)
Exercise 3 – Use the blocks
Write 53 as 5 tens, 3 ones.
Not enough ones. Trade 1 ten for 10 ones. Now: 4 tens, 13 ones.
Ones: \(13 – 8 = 5\).
Tens: \(4 – 2 = 2\).
So \(53 – 28 = 25\).
\(25\)
Exercise 4 – Trade a ten
Write 41 as 4 tens, 1 one.
Not enough ones. Trade 1 ten for 10 ones. Now: 3 tens, 11 ones.
Ones: \(11 – 6 = 5\).
Tens: \(3 – 1 = 2\).
So \(41 – 16 = 25\).
\(25\)
Exercise 5 – Count back
Split 49 into 40 and 9. Go back 40 from 86 to 46. Then go back 9 from 46 to 37.
\(86 – 49 = 37\)
Exercise 6 – Zero ones
Write 70 as 7 tens, 0 ones.
Not enough ones. Trade 1 ten for 10 ones. Now: 6 tens, 10 ones.
Ones: \(10 – 4 = 6\).
Tens: \(6 – 3 = 3\).
So \(70 – 34 = 36\).
\(36\)
Exercise 7 – Subtract from a ten
Write 90 as 9 tens, 0 ones.
Not enough ones. Trade 1 ten for 10 ones. Now: 8 tens, 10 ones.
Ones: \(10 – 8 = 2\).
Tens: \(8 – 5 = 3\).
So \(90 – 58 = 32\).
\(32\)
Exercise 8 – Missing part
The missing part is the whole minus the known part: \(64 – 29\).
Ones: 4 is less than 9, so trade. 64 is 5 tens and 14 ones. \(14 – 9 = 5\) and \(5 – 2 = 3\).
Check: \(35 + 29 = 64\).
\(35\)
Exercise 9 – Count up
Count up from 57 to 83: first to 60 (3 more), then to 80 (20 more), then to 83 (3 more).
\(3 + 20 + 3 = 26\)
\(83 – 57 = 26\)
Exercise 10 – Check with addition
Ones: 2 is less than 8, so trade. 62 is 5 tens and 12 ones. \(12 – 8 = 4\) and \(5 – 3 = 2\). So the difference is 24.
Check: \(24 + 38 = 62\). It matches.
\(24\)
Exercises 11 and up
Exercise 11 – Compare differences
\(92 – 47 = 45\). Trade 1 ten: 8 tens 12 ones, so \(12 – 7 = 5\) and \(8 – 4 = 4\).
\(81 – 39 = 42\). Trade 1 ten: 7 tens 11 ones, so \(11 – 9 = 2\) and \(7 – 3 = 4\).
45 is greater than 42 by \(45 – 42 = 3\).
\(92 – 47\) is greater, by 3
Exercise 12 – Find the error
Maya took the smaller digit from the larger digit in each place: \(5 – 1 = 4\) and \(7 – 4 = 3\). But 1 one is not enough to take away 5 ones, so she must trade a ten.
Correct work: 71 is 6 tens and 11 ones. \(11 – 5 = 6\) and \(6 – 4 = 2\).
Check: \(26 + 45 = 71\).
\(26\)
Exercise 13 – Blocks for 95
Write 95 as 9 tens, 5 ones.
Not enough ones. Trade 1 ten for 10 ones. Now: 8 tens, 15 ones.
Ones: \(15 – 8 = 7\).
Tens: \(8 – 6 = 2\).
So \(95 – 68 = 27\).
\(27\)
Exercise 14 – Explain the trade
73 is 7 tens and 3 ones. After the trade it is 6 tens and 13 ones.
\(13 – 6 = 7\) ones and \(6 – 4 = 2\) tens.
\(27\)
Exercise 15 – Take away a little extra
Taking away 20 removes 1 more than taking away 19. So the answer is 1 too small, and adding 1 puts it right.
\(78 – 20 = 58\) and \(58 + 1 = 59\).
\(59\)
Exercise 16 – Add to subtract
Adding to 37 until you reach 52 finds the gap between them, and the gap is \(52 – 37\).
37 to 40 is 3, and 40 to 52 is 12. \(3 + 12 = 15\).
Check: \(37 + 15 = 52\).
\(15\)
Exercise 17 – Sticker book
Subtract: \(84 – 37\).
84 is 7 tens and 14 ones. \(14 – 7 = 7\) and \(7 – 3 = 4\).
Jamal has 47 stickers.
Exercise 18 – Apple stand
Find the missing part: \(96 – 58\).
96 is 8 tens and 16 ones. \(16 – 8 = 8\) and \(8 – 5 = 3\).
Check: \(38 + 58 = 96\).
38 apples are left.
Exercise 19 – Ball game
Find \(72 – 29\). Not enough ones, so trade 1 ten: 72 is 6 tens and 12 ones.
\(12 – 9 = 3\) and \(6 – 2 = 4\).
43 fans are still at the game.
Exercise 20 – Bead bracelets
First: \(65 – 28\). Trade 1 ten: 5 tens and 15 ones. \(15 – 8 = 7\) and \(5 – 2 = 3\), so 37 beads are left.
Next: \(37 – 19\). Trade 1 ten: 2 tens and 17 ones. \(17 – 9 = 8\) and \(2 – 1 = 1\), so 18 beads are left.
18 beads
Exercise 21 – Pages read
Find the gap between 67 and 91 by counting up: 67 to 70 is 3, 70 to 90 is 20, and 90 to 91 is 1.
\(3 + 20 + 1 = 24\)
Diego read 24 more pages.
Exercise 22 – Cookie sale
\(95 – 48\): 95 is 8 tens and 15 ones. \(15 – 8 = 7\) and \(8 – 4 = 4\).
Check: \(47 + 48 = 95\).
47 cookies are left.
Key facts behind this subtract within 100 answers
- Trade 1 ten for 10 ones when the ones on top are too few.
- The difference is the answer to a subtraction problem.
- Counting back and counting up both find the same difference.
- Check subtraction with addition: difference + smaller number = whole.
- A bar model shows a whole and two parts.
How to use this subtract within 100 answers
Cover each solution, solve the exercise again, then uncover it and compare every line. If your answer differs, find the first step that changed and redo the exercise from there.
Download the subtract within 100 answers as a PDF with the button below and keep it with your notes.
Download the subtract within 100 answers as a PDF with the button below and keep it with your notes.
Download the subtract within 100 answers as a PDF with the button below and keep it with your notes.
All Grade 2 chapters: Grade 2 math.
