Unit 3 Operations with Positive Fractions and Decimals

Emily took 132.4 hours to train for her marathon. Jessica is going to run the same marathon but she trained 1.45 times as long as Emily. Based on this information, which statement is true?

• Jessica trained longer because 132.4 + 1.45 = 133.85

• Jessica trained longer because 132.4 + 1.45 = 146.9

• Jessica trained longer because 132.4 x 1.45 = 191.98

• Jessica trained longer because 132.4 x 1.45 = 72.820

Answer explanation

TIMES is the key word! You would multiply on this problem.

Remember! You don't have to line-up the decimals when you are multiplying, but you do have to move your decimal to the left for each number standing behind a decimal in the original problem.

Show work where you have corrected your error!

Tags

CCSS.5.NBT.B.7

Mona is making brownies that require 3/4 cup of sugar. She wants to make 1/3 of the recipe. How many cups of sugar should she use to make the brownies?

• 9/4

• 1/4

• 1/3

• 5/12

Answer explanation

The word, "OF, " right after the fraction is a great clue in this problem.

You should have multiplied.

I know it seems strange, but if you are only taking a part of something, you are going to multiply and not divide.

Tags

CCSS.5.NF.B.4

CCSS.5.NF.B.6

Norma went to The Candy Palace and bought Jelly Belly's for $3.20 per pound. What would she pay for 3 ½ lbs. of Jelly Belly's?

• $11.20

• $6.70

• $12.56

• 9.70

Answer explanation

Did you change 3 1/2 to its decimal name?

If so, you could easily multiply a decimal number by a decimal number in this problem.

Show your work to prove you have fixed your error.

Tags

CCSS.5.NBT.B.7

CCSS.5.NF.B.4

CCSS.5.NF.B.6

Sam was 4.25 feet tall in the fourth grade. By the time he was in eighth grade, he had grown 1 ⅖ times his height in the fourth grade. How tall was Sam when he reached the eighth grade?

• 21.25 feet tall

• 4.50 feet tall

• 5.50 feet tall

• 5.95 feet tall

Answer explanation

This problem has a great clue word with "times."

You should have multiplied.

The best way is to change 1 2/5 to its decimal name and then multiplied the two decimal numbers.

Try again and prove you've got it by showing your work.

Tags

CCSS.5.NF.B.4

CCSS.5.NF.B.5

CCSS.5.NF.B.6

Sandra is making trail mix bags for party favors using 6 ⅕ cups of the mix. She plans to use 1/2 of a cup for each bag. How many bags is Sandra preparing?

• 6 1/5

• 12 2/5

• 3 1/10

• 5 6/8

Answer explanation

This one is super tricky! You might have been fooled by the word "of," right after the fraction. This problem is a rare one where the "of" word does not help.

Think about this, if she has 6 1/5 cups of trail mix and she is splitting it up in bags by only scooping out 1/2 of a cup, she is going to have MORE bags than 6 1/5 cups.

Drawing a picture might help on this one.

Since she is splitting up the trail mix, you would divide. And remember, with division, you have to keep, change, flip!

Tags

CCSS.5.NF.B.3

CCSS.5.NF.B.6

Which expression is equivalent to 7/8 ÷ 4/5

• 7/5 ⋅ 8/4

• 7/8 ⋅ 5/4

• 8/7 ⋅ 4/5

• 8/7 ⋅ 5/4

Answer explanation

These are freebie questions! You should get these with no sweat!

Just remember the division rule of keep, change, flip. Change the problem using this rule and you will see your answer!

Tags

CCSS.5.NF.B.3

CCSS.5.NF.B.4

CCSS.5.NF.B.7

Jacob purchased concrete to fill a hole for $19.53. The concrete costs $13.95 per pound. How many pounds of concrete did Jacob buy?

Answer explanation

Did you divide or multiply.

If Jacob spent $19.53 at the cash register, you are not going to have an answer higher than that! That is the total he spent and you are looking for part of the answer to see how his total became $19.53.

You should have divided and I'll admit, it's a doozy! But you have the skills to show me you know how to do it!

Tags

CCSS.5.NBT.B.7

In the expression 6p, p represents a rational number. What value of p makes the expression equal a number more than 6?

• 12/10

• 4/5

• 12/12

• 2/3

Answer explanation

Remember, you are multiplying 6 times a mystery number. (6p means "side by side multiply.")

Any whole number multiplied by a proper fraction will make the product less.

Any whole number multiplied by an improper fraction will make the product more.

Wanna know the CHEAT METHOD? It's completely legal----

Cover up your question and look at your answer choices. You should see that all the fractions are proper, except for one who looks to be a little sus. Did you find it?

Tags

CCSS.5.NF.B.4

CCSS.5.NF.B.5

CCSS.5.NF.B.6

Which two expressions each represent 4/18

• 
• 
• 
• 

Answer explanation

ALWAYS, ALWAYS, ALWAYS label the cowboy and the horse but using a "c" and "h." Then, play Odd Man Out with your answer choices. One will have the cowboy in the wrong spot. Do you see it?

Tags

CCSS.4.NF.A.1

CCSS.4.NF.A.2

A baker wants to slice a cake that is 12/15 feet long into pieces that are 1/16 pieces. Which expression can also be used to calculate the number of pieces that can be cut from the cake?

• 12/15 ⋅ 16/1

• 12/1 ⋅ 16/15

• 15/12 ⋅ 1/16

• 15/12 ⋅ 16/1

Answer explanation

Hopefully you realized you you are taking part of a cake and cutting it in to more pieces...that's division!

Remember the division rule! Keep Change Flip!

Tags

CCSS.5.NF.B.3

CCSS.5.NF.B.4

CCSS.5.NF.B.6