Chapter 4 - Addition

To find about how many, you can

• regroup

• estimate

• front-end estimation

When you estimate a sum by adding the front digit of each addend, you are using

• regroup

• estimate

• front-end estimation

Do you need to regroup to find the sum 129 + 138?

• yes

• no

Do you need to regroup to find the sum 321 + 432?

• yes

• no

ROUND AND ESTIMATE THE SUM

267 + 193 =

• 210 + 110 = 320

• 300 + 200 = 500

• 200 + 100 = 300

ROUND AND ESTIMATE THE SUM

$5.92 + $3.25 =

• $6.00 + $3.00 = $9.00

• $5.00 + $4.00 = $9.00

• $5.90 + $3.20 = $9.10

USE FRONT-END ESTIMATION TO ESTIMATE THE SUM

420 + 589 =

• 400 + 500 = 900

• 400 + 600 = 1,000

• 500 + 600 = 1,100

USE FRONT-END ESTIMATION TO FIND THE SUM

6,528 + 1,347 =

• 6,500 + 1,300 = 7,800

• 6,000 + 1,000 = 7,000

• 7,000 + 2,000 = 9,000

FIND THE SUM. ESTIMATE TO CHECK.

419 + 451 =

FIND THE SUM. ESTIMATE TO CHECK.

127 + 315 + 299 =