2nd grade · Math · Unit 3 of 18
Adding to 100
Bigger adding and take-aways
What your child practices
Two-digit adding and subtracting by working with tens and ones, including making a new ten.
New York State Learning Standards learning standard: NY-2.NBT.5; NY-2.OA.1a · adding and subtracting within 100 using place value, including word problems
How we explain it
Children can open this short lesson before they practice.
- Add the tens first.
- Then add the ones.
- Put the two answers together. To take away, work the same way.
Example: 34 + 25 = ? Tens: 30 + 20 = 50. Ones: 4 + 5 = 9. 50 + 9 = 59. Answer: 59
Adding to 100 in New York
In the New York State Learning Standards, this is unit 3 of 18 in 2nd grade Math, after Facts to 20 and before Measuring.
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.
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 96 − 24?
96 − 24 = ?
- 72
- 67
- 74
72
Hint: Take away the tens: 90 − 20 = 70. Take away the ones: 6 − 4 = 2.
Question 2
What is 51 + 16?
51 + 16 = ?
- 57
- 67
- 61
67
Hint: Add the tens: 50 + 10 = 60. Add the ones: 1 + 6 = 7. Together: 67.
Question 3
What is 34 + 24?
- 64
- 58
- 55
58
Hint: Add the tens: 30 + 20 = 50. Add the ones: 4 + 4 = 8. Together: 58.
Question 4
Ollie has 20 stickers. He gets 21 more. How many stickers now?
⭐20 + 21- 46
- 37
- 41
41
Hint: Add them together: 20 + 21. Add the tens, then the ones.
Question 5
What is 31 + 30?
31 + 30 = ?
- 63
- 61
- 55
61
Hint: Adding tens? Only the tens change: 3 tens + 3 tens = 6 tens.
Question 6
What is 49 + 30?
49 + 30 = ?
- 81
- 79
- 74
79
Hint: Adding tens? Only the tens change: 4 tens + 3 tens = 7 tens.