In this Grade 2 mental math worksheet, second graders practice adding tens like 10, 20, and 30 within 100. Sorting separates problems that add just ten from problems that add larger tens, and fill-ins guide students to raise only the tens digit while keeping ones the same. True or false items reinforce that whole tens leave the ones unchanged, making these problems fast and reliable for Grade 2 learners.
Style:
Mental Math Within 100
Part A: Sort the Words
Sort each word or number into the correct category box.
54 + 1027 + 2041 + 1063 + 3018 + 1035 + 40
Add 10
Add 20, 30, or more
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 54 + 10 = 64 by raising the tens digit by one.
2. 27 + 20 = 47 by adding two tens in your head.
3. 63 + 30 = 93 by adding three tens.
4. Adding 10 to 41 changes only the tens digit, giving 51.
5. 35 + 40 = 75 by jumping four tens up from 35.
Part C: True or False?
Read each statement. Circle True or False.
1. When you add 10 to any number, only the tens digit changes.
True False
2. 27 + 20 equals 29 because you just add the 2.
True False
3. To add 35 + 40 mentally, you can count four tens up from 35.
True False
4. Adding a number that ends in zero is harder than adding ones.
True False
Mental Math Within 100
★ Part A: Sort the Words
Sort each word or number into the correct category box.
54 + 1027 + 2041 + 1063 + 3018 + 1035 + 40
Add 10
Add 20, 30, or more
★ Part B: Fill in the Blank
Write the missing word or number on each line.
1) 54 + 10 = 64 by raising the tens digit by one.
2) 27 + 20 = 47 by adding two tens in your head.
3) 63 + 30 = 93 by adding three tens.
4) Adding 10 to 41 changes only the tens digit, giving 51.
5) 35 + 40 = 75 by jumping four tens up from 35.
★ Part C: True or False?
Read each statement. Circle True or False.
1) When you add 10 to any number, only the tens digit changes.
True
False
2) 27 + 20 equals 29 because you just add the 2.
True
False
3) To add 35 + 40 mentally, you can count four tens up from 35.
True
False
4) Adding a number that ends in zero is harder than adding ones.
True
False
Ready to Practice?
Complete each section carefully.
10 Questions
15-20 minutes
Auto-graded
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