ESTIMATE IT!
Estimate: 5/8 + 7/15
Round both to 1/2 → 1/2 + 1/2
Answer: About 1
1/4 + 2/3
1/4 → 3/12
2/3 → 8/12
3/12 + 8/12 = 11/12
3/5 – 1/10
6/10 – 1/10 = 5/10 = 1/2
Luis ate 1/3 of a pizza at lunch and 1/6 at dinner. How much did he eat total?
2/6 + 1/6 = 1/2 pizza
Find the sum: 3.2 + 4.07
7.27
Estimate: 7/10 – 2/9
8/10 → 1
2/9 → 0
1 + 0 =
Answer: About 1
5/6 + 1/8
5/6 → 20/24
1/8 → 3/24
20/24 + 3/24 = 23/24
7/8 – 1/4
7/8 – 2/8 = 5/8
A class spent 3/8 of an hour reading and 1/4 of an hour discussing.
How long did they work altogether?
3/8 + 2/8 = 5/8 hour
Find the difference: 9.8 – 2.35
7.45
Estimate: 3/4 + 1/8
3/4 → 1
1/8 → 0
1 + 0 =
about 1
7/12 + 2/9
7/12 → 21/36
2/9 → 8/36
21/36 + 8/36 = 29/36
5/6 – 7/18
15/18 – 7/18 = 8/18 = 4/9
Bria bought ½ pound of turkey and 2/3 pound of ham.
How many pounds of meat did she buy?
3/6 + 4/6 = 7/6 or 1 1/6 pounds
What is 48.6 ÷ 3?
16.2
Estimate: 5/6 + 3/8
5/6 → 1
3/8 → 1/2
1 + 1/2 =
about 1 1/2
A recipe uses 1/5 cup of oil and 3/4 cup of milk. How much liquid total?
1/5 → 4/20
3/4 → 15/20
4/20 + 15/20 = 19/20 cups
A ribbon is 9/10 meter long. A student cuts off 2/5 meter. How much ribbon is left?
9/10 – 4/10 = 5/10 or 1/2 meter
A jogger ran 5/6 mile, stopped for water, then ran 1/3 mile more.
How far total?
5/6 + 2/6 = 7/6 or 1 1/6 miles
12.03 + 0.89 + 3.5
16.42
Marla estimates 4/5 – 1/6 ≈ 1/2.
Is this reasonable?
Ⓐ The estimate is reasonable because Marla used the closest benchmark fractions to subtract.
Ⓑ The estimate is reasonable because Marla used benchmark fractions that are not close to subtract.
Ⓒ The estimate is NOT reasonable because Marla used the closest benchmark fractions to subtract.
Ⓓ The estimate is NOT reasonable because Marla used benchmark fractions that are not close to subtract.
Ⓓ The estimate is NOT reasonable because Chen used benchmark fractions that are not close to subtract.
Maria biked 2/3 of a mile, rested, then biked 5/12 of a mile more.
How far did she bike?
2/3 → 8/12
8/12 + 5/12 = 13/12 or 1 1/12 miles
11/12 – 5/18
33/36 – 10/36 = 23/36
Rey baked 3/4 pan of brownies. He gave away 2/5 of a pan.
How much is left?
15/20 – 8/20 = 7/20 pan
72.25 ÷ 5?
14.45