Add & Subtract Within 1000 — Answer Key
Part A: Sort the Words
Sort each word or number into the correct category box.
1. Sort each sum by whether the total is exactly 700 or exactly 900.
Equals 700
200 + 500300 + 400100 + 600 Equals 900
400 + 500600 + 300500 + 400 Grouping sums by total reinforces that 2+5 hundreds is 700 and 4+5 hundreds is 900.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 200 + 300 = 500
2 + 3 = 5, so 200 + 300 equals 5 hundreds or 500.
2. 400 + 500 = 900
4 hundreds plus 5 hundreds makes 9 hundreds, which is 900.
3. 600 + 200 = 800
6 + 2 = 8, so 600 + 200 equals 800.
4. 100 + 700 = 800
1 + 7 = 8, so the sum is 8 hundreds or 800.
5. 300 + 300 = 600
3 + 3 = 6, so 300 + 300 equals 600.
Part C: True or False?
Read each statement. Circle True or False.
1. 500 + 400 equals 900.
True False
5 + 4 = 9, so 500 + 400 is indeed 900.
2. 200 + 600 equals 700.
True False
2 + 6 = 8, so the correct sum is 800, not 700.
3. 300 + 500 equals 800.
True False
3 + 5 = 8, so 300 + 500 equals 800.
4. 400 + 400 equals 900.
True False
4 + 4 = 8, so 400 + 400 equals 800, not 900.