10 printable sets · answer key on every set

Addition With Regrouping to 100 Worksheets

CCSS 2.NBT.B.5
20 problems per set
Answer key included

What this skill is

Two-digit addition where the ones column crosses ten — 47 + 38.

When it comes up: Middle of second grade. CCSS 2.NBT.B.5 expects fluency by year's end.

The mistake to watch for

Writing the full two-digit sum in the ones column: 47 + 38 written as 715, because 7 + 8 = 15 goes in whole.

How to help

Ask "how many tens, how many ones?" for every sum over nine. Fifteen is one ten and five — the ten moves next door.

Next: Subtraction within 100.

A worked example

Try 47 + 38. Ones: 7 + 8 = 15, so write 5 and carry 1 ten. Tens: 4 + 3 + 1 = 8. The answer is 85.

Words to know

regroup: To trade 10 ones for 1 ten (or 1 ten for 10 ones) when you add or subtract.
carry: To move extra tens (or hundreds) to the next column when you add.
sum: The answer you get when you add.
ten: The number 10, one more than nine.
digit: One of the ten number symbols 0 to 9. The number 47 has two digits.

Practice

Add. Regroup when you need to.

Showing Set 1 · 20 problems

84 + 6 =
56 + 4 =
86 + 7 =
59 + 22 =
42 + 29 =
15 + 46 =
39 + 51 =
13 + 7 =
69 + 27 =
83 + 8 =
8 + 33 =
19 + 72 =
29 + 9 =
45 + 49 =
41 + 19 =
26 + 39 =
54 + 39 =
88 + 6 =
19 + 76 =
67 + 3 =

Download this set20 problems · answer key included PDF

Answer key

All 10 sets

Each set is a different list of 20 problems with its own answer key. Use the buttons above to look at one on this page, or download any of them as a PDF.

How these sheets were made

Problems are generated for each set and checked against 2.NBT.B.5 before the sheet is built — no duplicates, and every problem falls inside the standard's number range.