2nd grade · Math · Unit 2 of 16
Facts to 20
Add and take away
What your child practices
Fluent facts to 20 using strategies like making ten and thinking addition to subtract.
Alaska content standards learning standard: 2.OA.2 · fluently adding and subtracting within 20
How we explain it
Children can open this short lesson before they practice.
- Use 10 as a stepping stone.
- Break one number to make a 10 with the other.
- Then add what is left over.
Example: 8 + 5 = ? 8 needs 2 more to make 10. Take 2 from 5. That leaves 3. 10 + 3 = 13. Answer: 13
Facts to 20 in Alaska
In the Alaska content standards, this is unit 2 of 16 in 2nd grade Math, after Bigger or Smaller and before Adding to 100.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Source: Alaska Department of Education and Early Development
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is 4 + 7?
- 7
- 11
- 17
11
Hint: Make a ten! 4 + 6 = 10, then add 1 more to get 11.
Question 2
What is 5 + 3?
5 + 3 = ?
- 8
- 11
- 3
8
Hint: Start at 5 and count up 3 more.
Question 3
What number is missing?
4 + = 7
- 3
- 9
- 5
3
Hint: Count up from 4 to 7. How many jumps did you make?
Question 4
What is 11 − 8?
11 − 8 = ?
- 9
- 6
- 3
3
Hint: Think addition: 8 + ? = 11. Or start at 11 and count back 8.
Question 5
What is 4 + 9?
4 + 9 = ?
- 13
- 8
- 7
13
Hint: Make a ten! 4 + 6 = 10, then add 3 more to get 13.
Question 6
What is 14 − 2?
14 − 2 = ?
- 7
- 17
- 12
12
Hint: Think addition: 2 + ? = 14. Or start at 14 and count back 2.