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Dividing Decimals | Grade 5

Student Concept Worksheet Answers
1
4.2
8.4 / 2 = 4.2 (Estimate: 8 / 2 = 4, so answer should be close to 4)
2
3.1
15.5 / 5 = 3.1 (Estimate: 15 / 5 = 3, so answer should be close to 3)
3
30
12 / 0.4 = 30. Step 1: 0.4 becomes 4. Step 2: 12 becomes 120. Step 3: 120 / 4 = 30
4
8 pieces
7.2 / 0.9 = 8. Move decimals: 72 / 9 = 8. Maria can make 8 pieces.
Practice Worksheet Answers

Part A: Divide Decimals by Whole Numbers

# Problem Answer Work
16.4 / 23.2Decimal straight up
29.9 / 33.3Decimal straight up
312.5 / 52.5Decimal straight up
418.4 / 44.6Decimal straight up
525.2 / 64.2Decimal straight up
636.8 / 84.6Decimal straight up

Part B: Divide Whole Numbers by Decimals

# Original Becomes Answer
78 / 0.480 / 420
815 / 0.5150 / 530
924 / 0.6240 / 640
1018 / 0.3180 / 360

Part C: Mixed Practice

# Problem Answer Explanation
1114.7 / 72.1Decimal straight up
124.8 / 0.8648 / 8 = 6
1332.4 / 93.6Decimal straight up
147.2 / 0.9872 / 9 = 8

Part D: Word Problems

15
$1.75
$8.75 / 5 = $1.75 per notebook
16
24 pieces
12 / 0.5 = 120 / 5 = 24 pieces
17
3.9 miles per hour
15.6 / 4 = 3.9 miles per hour
18
8 batches
6 / 0.75 = 600 / 75 = 8 batches

Challenge Questions:

#19: 24 / 0.5 is greater. When you divide by a number less than 1 (like 0.5), the answer is bigger than the original. 24 / 0.5 = 48, while 24 / 2 = 12.

#20: 3.6 / 4 = 0.9. Since 3.6 is 10 times smaller than 36, the answer is also 10 times smaller: 9 / 10 = 0.9

FAST Practice Quiz Answers
1
B) 2.1
8.4 / 4 = 2.1. The decimal point goes straight up. Estimate: 8/4 = 2, so 2.1 is reasonable.
2
C) 30
15 / 0.5 = 150 / 5 = 30. Move both decimals right one place.
3
A) $3.15
$12.60 / 4 = $3.15. Each friend gets $3.15.
4
Select: 8 / 0.4, 6 / 0.5, and 48.6 / 3
8 / 0.4 = 20 (greater than 10)
25.5 / 5 = 5.1 (NOT greater than 10)
6 / 0.5 = 12 (greater than 10)
48.6 / 3 = 16.2 (greater than 10)
9.8 / 7 = 1.4 (NOT greater than 10)
5
C) 30 pieces
18 / 0.6 = 180 / 6 = 30 pieces
6
D) Both A and C are correct explanations
Both explanations work: A uses rounding (17.8 to 18), and C uses the inverse operation (3 x 6 = 18).
FAST Quiz Scoring Guide
Score Interpretation Recommended Action
6/6 Mastery Ready for IXL practice on more complex decimal operations. Consider multi-step problems.
4-5/6 Approaching Mastery Review missed concepts. Focus on either decimal placement or dividing BY decimals, whichever was missed.
2-3/6 Developing Reteach with money examples and estimation. Focus on understanding why we move decimals.
0-1/6 Needs Intervention Small group instruction. Review whole number division first, then introduce decimals gradually with base-ten blocks.
FAST Success Kit | Grade 5 | FL B.E.S.T. Standard: MA.5.NSO.2.5 | Answer Key - Teacher Use Only