2nd Grade Adding Within 100 Worksheet Solutions (PDF)
This add within 100 answers for 2nd Grade covers adding within 100 (Common Core 2.NBT.B.5, 2.NBT.B.6), with a free PDF to print.
Each answer shows the ones, then the tens, with any regrouping. Compare your work with these steps and fix any slips.
Grade 2 · Common Core State Standards: 2.NBT.B.5, 2.NBT.B.6
Add within 100 answers: exercises 1 to 10
Exercise 1 – Add tens
Ones: \(0 + 0 = 0\).
Tens: \(3 + 4 = 7\).
\(30 + 40 = 70\).
70
Exercise 2 – Blocks without regrouping
Ones: \(3 + 4 = 7\).
Tens: \(2 + 1 = 3\).
\(23 + 14 = 37\).
37
Exercise 3 – Tens and ones
Ones: \(2 + 6 = 8\).
Tens: \(5 + 3 = 8\).
\(52 + 36 = 88\).
88
Exercise 4 – Add a group of tens
Ones: \(3 + 0 = 3\).
Tens: \(6 + 3 = 9\).
\(63 + 30 = 93\).
93
Exercise 5 – Add a one-digit number
Ones: \(7 + 6 = 13\), which is 1 ten and 3 ones.
Tens: \(4 + 0 + 1 = 5\) (with the regrouped ten).
\(47 + 6 = 53\).
53
Exercise 6 – First regrouping
Ones: \(8 + 5 = 13\), which is 1 ten and 3 ones.
Tens: \(2 + 1 + 1 = 4\) (with the regrouped ten).
\(28 + 15 = 43\).
43
Exercise 7 – Regroup the ones
Ones: \(6 + 7 = 13\), which is 1 ten and 3 ones.
Tens: \(3 + 2 + 1 = 6\) (with the regrouped ten).
\(36 + 27 = 63\).
63
Exercise 8 – Bigger regrouping
Ones: \(9 + 4 = 13\), which is 1 ten and 3 ones.
Tens: \(4 + 3 + 1 = 8\) (with the regrouped ten).
\(49 + 34 = 83\).
83
Exercise 9 – Jumps on a number line
Hop 20 to 77. Then hop 5 to 82.
\(57 + 25 = 82\). 82
Exercise 10 – Sum near ninety
Ones: \(8 + 9 = 17\), which is 1 ten and 7 ones.
Tens: \(6 + 1 + 1 = 8\) (with the regrouped ten).
\(68 + 19 = 87\).
87
Exercises 11 and up
Exercise 11 – Sum over ninety
Ones: \(4 + 8 = 12\), which is 1 ten and 2 ones.
Tens: \(7 + 1 + 1 = 9\) (with the regrouped ten).
\(74 + 18 = 92\).
92
Exercise 12 – Compare two sums
\(46 + 27 = 73\). \(39 + 36 = 75\). Since 75 is greater than 73, the second sum is greater.
\(39 + 36\) is greater
Exercise 13 – Missing digit
The ones must make a number that ends in 1. \(? + 7\) ends in 1 when \(4 + 7 = 11\). So the digit is 4.
Check: \(44 + 37 = 81\). 4
Exercise 14 – Break apart
\(54 + 20 = 74\). Then \(74 + 9 = 83\).
83
Exercise 15 – Three addends
Ones: \(2 + 5 + 1 = 8\).
Tens: \(1 + 2 + 3 = 6\).
\(12 + 25 + 31 = 68\).
68
Exercise 16 – Four addends
Ones: \(1 + 4 + 7 + 6 = 18\), which is 1 ten and 8 ones.
Tens: \(2 + 3 + 1 + 2 + 1 = 9\) (with the regrouped ten).
\(21 + 34 + 17 + 26 = 98\).
98
Exercise 17 – Farmers market apples
Ones: \(7 + 8 = 15\), which is 1 ten and 5 ones.
Tens: \(4 + 3 + 1 = 8\) (with the regrouped ten).
\(47 + 38 = 85\).
Ana sold 85 apples.
Exercise 18 – Library cart
Ones: \(9 + 6 = 15\), which is 1 ten and 5 ones.
Tens: \(2 + 3 + 1 = 6\) (with the regrouped ten).
\(29 + 36 = 65\).
65 books
Exercise 19 – Little League runs
Ones: \(4 + 8 + 1 = 13\), which is 1 ten and 3 ones.
Tens: \(2 + 1 + 3 + 1 = 7\) (with the regrouped ten).
\(24 + 18 + 31 = 73\).
73 runs
Exercise 20 – Bake sale tables
Ones: \(5 + 2 + 8 + 6 = 21\), which is 2 tens and 1 ones.
Tens: \(1 + 2 + 1 + 2 + 2 = 8\) (with the regrouped tens).
\(15 + 22 + 18 + 26 = 81\).
81 muffins
Exercise 21 – Sticker collection
Step 1: \(56 + 27 = 83\).
Step 2: \(83 + 9 = 92\).
92 stickers
Exercise 22 – Can drive
Ones: \(8 + 5 + 7 = 20\), which is 2 tens and 0 ones.
Tens: \(4 + 3 + 1 + 2 = 10\) (with the regrouped tens).
\(48 + 35 + 17 = 100\).
Yes. They have exactly 100 cans.
Key facts behind this add within 100 answers
- Add ones first, then tens.
- Ten ones can be regrouped as 1 ten: \(8 + 7 = 15\) is 1 ten and 5 ones.
- On a number line, hop by tens and then by ones.
- To add three or four numbers, add all the ones, then all the tens.
- Estimating with tens helps you check an answer.
How to use this add 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.
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All Grade 2 chapters: Grade 2 math.
