Math Topic 8 Review

What is the sum of 243, 132, and 221?

What is a reasonable estimate for the sum of 171 + 69?

Select all that apply.

• 175 + 70 = 245

• 100 + 60 = 160

• 170 + 70 = 240

• 175 + 75 = 250

• 130 + 70 = 200

Subtract 382 - 148 mentally. Choose the answer below.

• 235

• 233

• 230

• 234

• 334

Use mental math to add 332 and 154. Which of these shows how to break apart the numbers into hundreds, tens, and ones?

• Break 332 into 320 + 12. Break 154 into 150 + 14.

• Break 332 into 100 + 230 + 2. Break 154 into 100 + 52 + 2.

• Break 332 into 300 + 30 + 2. Break 154 into 100 + 50 + 4.

• Break 332 into 300 + 16 + 16. Break 154 into 100 + 27 + 27.

Estimate the difference of 765 - 333. Which equation below is reasonable?

• 770 - 330 = 440

• 700 - 400 = 300

• 800 - 300 = 500

• 800 - 30 = 770

Use mental math to find 634 - 528.

Select all equations that are true.

• 32 + 56 + 10 = 10 + 56 + 32

• (49 + 28) + 5 = 49 + (28 + 5)

• 56 + 890 = 890 + 56

• 82 + 0 = 82

• 45 + 27 = 27 + 35

Round the number 168 to the nearest ten. Type your answer below.

Round the number 239 to the nearest ten. Type the number below.

Round the number 155 to the nearest ten. Type your answer below.