Add Three Numbers is a free printable Grade 1 maths worksheet on associativity — choosing which pair to add first, aligned to Common Core standard 1.OA.B.3. It prints 12 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 18 of 25 · the same problems every time you open this link.

One paper per pupil

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Add Three Numbers

1.OA.B.3

NameDate

Work out each answer.

1.7 + 5 + 1 =

2.2 + 8 + 2 =

3.3 + 4 + 3 =

4.2 + 5 + 1 =

5.6 + 3 + 6 =

6.8 + 6 + 4 =

7.2 + 5 + 3 =

8.2 + 6 + 3 =

9.5 + 1 + 8 =

10.7 + 1 + 6 =

11.4 + 8 + 8 =

12.7 + 7 + 6 =

LessonPrint · 1.OA.B.3 · Set 18 · free to copy for classroom use

Answer key — Add Three Numbers

Set 18. Prints on its own sheet.

1.13
2.12
3.10
4.8
5.15
6.18
7.10
8.11
9.14
10.14
11.20
12.20

Last reviewed 2026-09-05. Aligned to 1.OA.B.3 of the Common Core State Standards for mathematics.