Estimation & Reasoning
Estimate the sum of 9/10 and 5/6. Write an equation.
(9/10 ≈ 1, 5/6 ≈ 1 → 1 + 1 = 2)
Select all expressions equal to 3/4:
7/20 + 2/5
19/20 − 1/5
34/7 − 9/10
7/20 + 2/5
19/20 − 1/5
5 7/9 − 3 2/3
2 1/9
1/6 + 1/8
7/24
Explain why you must rename 10 3/5 in
order to find 10 3/ 5 - 6/7
You
cannot subtract 6/7 from 3/ 5.
For a trip to the beach, Kelly drove for 5/6 hour and Joshua drove for 2/5 hour.
Estimate how much longer Kelly drove. Explain.
1/2 hour
1/7 + 2/5 using a common denominator.
What is the total?
5/35 + 14/35 = 19/35
4 1/2 − 2 3/4
1 3/4
For a trip to the beach, Kelly drove for
5/6 hour and Joshua drove for 2/5 hour.
A. Estimate how much longer Kelly drove
than Joshua. Explain how you found
your estimate.
B. How much longer did Kelly drive than
Joshua? Find the exact amount
A.
1/2 hour;
5/6 is close to 1 hour and 2/5 is close to 1
B. 13/30 hour
7 5/8 + 9 2/3 + 10 3/4
28 3/16
Cassidy had 8 7/10 inches of string. She used 5 3/8 inches.
Estimate how much string is left.
A 2
B 4
C 3
D 5
B – 4 inches
1/3 + 3/8
17/24
3 3/4 − 7/8
A. Why must you rename?
B. How do you rename?
2 7/8
Rename because 3/4 < 7/8
3 3/4 = 3 6/8
For an industrial arts class, Talia used
1/3 of a piece of wood for the base of
her project, 1/4 of the piece of wood for
a vertical support, and the rest for a
horizontal support. What fraction of
the piece of wood did Talia use as a
horizontal support?
5/12 of the wood
The fraction strips below can be used to
find the sum of two mixed numbers. What
is the sum? What is the difference? Show
your work.
Sum = 6 1/3
Difference = 1 1/6
Estimate the sum of 2 7/9 and 2 3/4. Explain.
6
Choose correct sums:
1/8 + 3/4 =
1/8 + 1/2 =
1/8 + 5/16 =
1/8 + 15/16 =
7/8, 5/8,7/16, 1 1/16
Triangle sides are 1 1/3 each.
Find the perimeter.
4
A carpenter needs a board that is 9 2/3 feet
long. He has a board that is 12 3/4
feet long. How much of the board must the
carpenter cut off? If the carpenter wants
another piece of wood that is 2 3/4 feet
long, how much of the board must the
carpenter cut off of the board that is
remaining?
3 1/12 feet; 1/3 foot
Fraction strips for two mixed numbers
are shown below. What is the sum of the
numbers? What is the difference? Show
your work.
Sum = 3 7/9
Difference = 2/3
Find the sum:
5/12+7/18
29/36
Find:
61/5−23/4
3 9/20
Maria baked 2 3/4 pies. Her family ate 1 5/8 pies.
How much pie is left?
1 1/8 pies
A baker had 7 1/2 cups of flour. She used 3 3/4 cups in the morning and 1 2/3 cups in the afternoon.
How much flour does she have left?
2 1/12 cups of flour
Is (5 4/8 + 7 3/4) − 4 2/4 a whole number? Explain.
No
Result = 8 3/4