Estimating / Rounding
Ben and his sister shared a large sandwich. Ben ate 3/5 of the sandwich and his sister ate 1/7 of the sandwich.
Estimate how much more Ben ate than his sister. Explain how you found your estimate.
1/2 of the sandwich
3/5 is close to 1/2 and 1/7 is close to 0.
1/2 - 0 = 1/2
Choose all the expressions that are equal to 2/3.
A. 1/6 + 1/2
B. 2/9 + 7/18
C. 5/12 + 1/4
D. 1 1/6 - 1/3
E. 2 - 1 1/3
A. 1/6 + 1/2
C. 5/12 + 14
E. 2 - 1 1/3
Ben and his sister shared a large sandwich. Ben ate 3/5 of the sandwich and his sister ate 1/7 of the sandwich.
How much more did Ben eat than his sister?
16/35 of the sandwich
Common denominator: 35
21/35 - 7/35 = 16/35
Sandra drove for 1/3 hour to get to the store. Then she drove 1/5 hour to get to the library. What fraction of an hour did Sandra drive in all?
8/15 of an hour
1/3 + 1/5 = 5/15 +3/15 = 8/15
Common denominator: 15
Tim has 5/12 of a jar of blackberry jam and 3/8 of a jar of strawberry jam. Write 5/12 and 3/8 using a common denominator.
Common denominator: 24
10/24 and 9/24
Which expression is the best estimate for 3 1/8 - 1 3/4?
A. 3 - 1
B. 3 - 2
C. 4 - 1
D. 4 - 2
B. 3 - 2
What number makes the statement true?
2 7/12 = 1 ____/12
19
2 7/12 = 1 19/12
Mona bought 3 3/8 pounds of cheddar cheese. She used 2 3/4 pounds to make sandwiches. Which expression shows how much cheese is left?
A. 3 3/8 + 2 3/4
B. 3 3/8 - 2 3/4
B. 3 3/8 - 2 3/4
Subtraction! (How much cheese is left)
1/4 + 3/8 = ________
1/4 + 7/10 = _______
1/4 + 11/12 = ________
5/8
19/20
1 1/6
A pelican has a wingspan of 8 1/5 feet. An eagle has a wingspan of 6 2/3 feet. How much longer is the wingspan of a pelican?
1 8/15 feet
8 1/5 - 6 2/3 =
A. 1/4 + ____ = 1 7/8
B. 4 - _____ = 2 5/8
Does 1 3/8 make A or B true?
A. False
B. True
Marie needs 2 1/4 yards of fabric. She already has 1 3/8 yards. How many more yards of fabric does she need?
7/8 yard
2 1/4 - 1 3/8 = 2 2/8 - 1 3/8 = 1 10/8 - 1 3/8 = 7/8
During a trip, Martha drove 1/6 of the time, Chris drove 1/4 of the time, and Juan drove the rest of the time. What fraction of the time did Juan drive?
7/12 of the time
1/6 + 1/4 = 2/12 + 3/12 = 5/12
1 - 5/12 = 7/12
Daily Double!
Reference #5 on pg. 449
Solve both A & B
Part A: 4/12 and 3/12
Common denominator: 12
Part B: 7/12 of the pizza
4/12 + 3/12 = 7/12
A. 1/18 + ____ = 10/18
B. 1/3 + _____ = 1/5
Does 1/2 make A or B true?
A. True
B. False
Mica read 1/6 of a book on Monday and 3/8 on Tuesday. Susan read 5/6 of the same book. How much more of the book has Susan read than Mica?
7/24
5/6 - (1/6 + 3/8) =
Subtract the sum of 4 3/4 and 5 2/3 from 12 1/2.
2 1/2
12 1/2 - (4 3/4 + 5 2/3) =
Diego wants to find 4 1/5 - 7/10.
Explain why he must rename 4 1/5 in order to do the subtraction.
He needs to find a common denominator. Also, 7/10 is a larger fraction than 1/5.
Gilberto worked 3 1/4 hours on Thursday, 4 2/5 on Friday, and 6 1/2 hours on Saturday. How many hours did he work in all during the three days?
14 3/20 hours
3 1/4 + 4 2/5 + 6 1/2 =
Common denominator: 20
2 5/8 + 1/2 =
2 5/8 + 1 3/16 =
3 1/8
3 13/16
To estimate the sum of two mixed numbers, Carla rounds one number to 3 and the other number to 7. Which is the number she rounds to 3?
A. 2 5/8
B. 2 11/30
C. 3 4/6
D. 3 7/9
A. 2 5/8
Mark is making a small frame in the shape of an equilateral triangle with the dimensions shown below. What is the perimeter of the frame?
A. 6 1/2 cm
B. 9 1/2 cm
C. 10 1/2 cm
C. 10 1/2 cm
Diego wants to find 4 1/5 - 7/10.
Explain how to rename 4 1/5 in order to do the subtraction.
3 12/10
Daily Double!
Reference #14 on pg. 451
4 2/5
1 8/10 + 2 3/5 = 1 8/10 + 2 6/10 =
3 14/10 = 4 4/10 = 4 2/5
A baker uses food coloring to color cake batter. He needs 4 1/8 ounces of green food coloring. The baker only has 2 1/2 ounces. How much more green food coloring does he need?
1 5/8 ounces
4 1/8 - 2 1/2 = 1 5/8