5th Grade MCA Review - Estimating with Fractions & Decimals

• 1

• 2

Answer explanation

Remember when you ESTIMATE, you make a smart guess...which often means you round!

So...

6/7 is ABOUT 1 whole and 11/12 is ABOUT 1 whole.

So, 1 + 1 = 2

Tags

CCSS.5.NF.A.1

CCSS.5.NF.A.2

This week after school, Hunter played soccer for 5.12 hours. He played baseball for 0.93 hour, and he played basketball for 2.07 hours. What is the best estimate of the sum of the time Hunter played sports this week?

• About 2 hours

• About 5 hours

• About 6 hurs

• About 8 hours

Answer explanation

Remember when we estimate we need to make a smart guess, and we often round!

so...

5.12 is ABOUT 5 hours

0.93 is ABOUT 1 hour

2.07 is ABOUT 2 hours

5 + 1 + 2 = 8 hours

• between 1 and 2

• between 2 and 3

• between 3 and 4

• between 8 and 9

Answer explanation

Remember when subtracting fractions that the denominators need to be the same!

So... 5 1/2 - 2 7/8 becomes...

5 4/8 - 2 7/8

But we can't do that! Borrow and it becomes...

4 12/8 - 2 7/8 = 2 5/8

This means our answer is between 2 and 3!

Tags

CCSS.7.NS.A.1C

• about 0 feet

• about 1 foot

Answer explanation

If we want to estimate, we need to round!

13/16 is ABOUT one whole

3/8 is ABOUT one half

One whole minus one half = one half!

Rachel's mother is running a marathon, which is 26.2 miles long. She has already run 13.9 miles. About how many more miles must she run before she finishes the marathon?

• 12 miles

• 14 miles

• 20 miles

• 40 miles

Answer explanation

Remember, when we estimate we need to ROUND!

26.2 is ABOUT 26

13.9 is ABOUT 14

26-14 - 12 miles!

• about 5 inches

• about 6 inches

Answer explanation

Remember, when we estimate, we round!

7/8 is ABOUT one whole

4 1/6 is ABOUT 4

1 + 4 = 5!