Multiply Divide Positive Negative Fractions Decimals

• Add -5 + 7.

• Subtract -5 - 7.
  

• Multiply -5 x 7.
  

• Divide -5 / 7.

When Multiplying/Dividing Mixed Numbers you MUST 1st...

• Find the square roots.

• Subtract.

• Turn them to IMPROPER FRACTIONS!

• Find common denominators.

When MULTIPLYING DECIMALS count the decimal places in each factor and ...

• Move that total amount of decimal places in your answer.

• Subtract.

• Find the square root.

• BE HAPPY!

(-11.3) × (-2.5)

• 79.1

• 13.8

• 22.597

• 28.25

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!

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.

1.44 ÷ (−0.4)

Mathematical Equivalence

ON

When multiplying or dividing decimals, if both numbers are negative what will the  sign of the answer be?

• + positive

• - negative

1.395 ÷ (-3.1) = ______

• -0.45

• 0.45

• 4.5

• -4.5

1.44 ÷ −0.4

• 36

• 3.6

• 126

• −3.6