Decimal Addition and Subtraction — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Grade 4: Rounded to the nearest whole, 4.78 + 3.21 estimates to which sum?
A) 7
B) 8
C) 9
D) 10
4.78 rounds to 5 and 3.21 rounds to 3, giving 8.
2. Grade 4: The actual sum of 4.78 + 3.21 is closest to which value?
A) 7.99
B) 8.99
C) 7.09
D) 8.09
4.78 + 3.21 = 7.99.
3. Grade 4: Rounded to the nearest tenth, 5.47 becomes which decimal?
A) 5.4
B) 5.5
C) 5.0
D) 6.0
Seven rounds the tenth up to 5.5.
4. Grade 4: A student estimated 6.82 + 2.15 as 10. Which whole-number estimate is more precise?
A) 8
B) 9
C) 10
D) 11
6.82 rounds to 7 and 2.15 rounds to 2, giving 9.
Part B: Fill in the Blank
Write the correct answer on each line.
1. Grade 4: Rounding 4.78 to the nearest whole gives 5.
Seven tenths rounds up to the next whole.
2. Grade 4: Rounding 3.21 to the nearest whole gives 3.
Two tenths rounds down to the same whole.
3. Grade 4: The estimated sum of 4.78 + 3.21 to the nearest whole is 8.
5 + 3 = 8.
4. Grade 4: The actual sum 4.78 + 3.21 equals 7.99.
Column addition gives seven and ninety-nine hundredths.
5. Grade 4: Rounded to the nearest tenth, 5.47 becomes 5.5.
Seven rounds the tenths digit up by one.