Patterns When Dividing by Decimals
What happens to a number when you divide it by 0.1?
The number becomes 10 times bigger.
The decimal moves one place to the right.
0.4 × 0.7 = ?
0.28
42.3 × 0.2
Round 42.3 to 42
About 8
A toy store orders 15 boxes of action figures with 24 in each.
How many toys total?
360 toys
What are the unknown numbers in the equation?
0.4 × 1.2 × 0.5 =
(0.4 × ____) × 1.2 = ____
(0.4 x 0.5) x 1.2 = 0.24
What happens when you divide a number by 0.01?
The number becomes 100 times bigger.
The decimal moves two places to the right.
1.6 × 0.5 = ?
0.8
26.9 ÷ 3
Round → 27 ÷ 3
About 9
A store orders 12 boxes of notebooks with 38 notebooks each.
How many notebooks total?
456 notebooks
What are the unknown numbers in the equation?
0.3 × 1.5 × 0.6 =
(0.3 × ____) × 1.5 = ____
(0.3 x 0.6) x 1.5 = 0.27
5.72 ÷ 0.1 = ?
57.2
0.32 × 0.9 = ?
0.288
A runner travels 285.7 miles over 5 days.
Estimate how many miles she runs per day.
Round → 300 ÷ 5
Round → 250÷ 5
About 60 miles/day
About 50 miles/day
A warehouse ships 18 crates with 56 books each.
How many books?
1,008 books
What are the unknown numbers in the equation?
0.25 × 1.2 × 4 =
(0.25 × ____) × 1.2 = ____
(0.25 x 4) x 1.2 = 1
93.8 ÷ 0.01= ?
9,380
A bag contains 0.85 pounds of flour.
A baker uses 0.4 of that amount.
How much flour does he use?
0.34 lb
Estimate the product:
6.78 × 4.1
About 28
A store buys 22 boxes with 75 pencils each, and 16 boxes with 48 pens each.
How many more pencils than pens?
Pencils: 22×75 = 1,650
Pens: 16×48 = 768
1650 - 786 = 882 more
What are the unknown numbers in the equation?
0.7 × 1.3 × 0.4 =
(0.7 × ____) × 1.3 = ____
(0.7 × 0.4) × 1.3 = 0.364
What happens when you divide a number by 0.001?
The number becomes 1000 times bigger.
The decimal moves three times to the right.
Explain how to place the decimal in 2.4 × 1.36.
Count three decimal places total → the product must have three decimal places.
Ellen drove 357.3 miles. For each gallon of gas, the car can travel 21 miles. Which estimates are the number of gallons of gas Ellen used between?
Select the two correct answers.
Ⓐ 1.7 gallons
Ⓑ 1.8 gallons
Ⓒ 17 gallons
Ⓓ 18 gallons
Ⓔ 170 gallons
Ⓕ 180 gallons
C and D
A company sells 14 crates with 128 folders each, and 10 crates with 92 binders each.
How many more folders than binders?
Folders: 1,792
Binders: 920
Difference: 872
What are the unknown numbers in the equation?
0.5 × 1.6 × 0.2 =
(0.5 × ____) × 1.6 = ____
(0.5 × 0.2) × 1.6 = 0.16