EnVision Math

Topic 2:

Lesson 2-2

Estimating Sums and Differences

2010-11

Ryan and Ariana Chelsie and Allison

Maryan and Brandon Saul and Jayla

Meadow and Mikayla Cameron, Jadyn & Ryan V.

Matthew and Nicholas

Elijah and Chase

How can I estimate sums and differences?

645 + 253 =600 300

900

398 + 121 =400 100

500

563 + 375 =600 400

1,000

5,317 + 1,734 =5,000 2,000

7,000

6,324 + 3,842 =6,000 4,000

10,000

72,694 + 17,789 =70,000 20,000

90,000

1,250 + 204 =1,300 200

1,500

542 + 27 =540 30

570

288 - 171 =300 200

100

5,323 – 2,611 =5,000 3,000

2,000

73,088 – 44,444 =70,000 40,000

30,000

892 - 35 =890 40

850

1,724 - 731 =1,700 700

1,000

1,931 – 1,884 =2,000 2,000

0

1,931 – 1,884 =

0

1,900 1,900

1,931 – 1,884 =

50

1,930 1,880

How can I estimate sums and differences?

$4.95 + $8.39 =$5.00 $8.00

$13.00

$9.45 - $6.72 =$9.00 $7.00

$2.00

$24.66 + $72.19 =$20.00 $70.00

$90.00

Let’s Practice

!

219 + 544 =200 500

700

86,128 – 28,017 =90,000 30,000

60,000

$8.79 + $9.13 =$9.00 $9.00

$18.00

1,576 - 910 =1,600 900

700

7,299 + 5,846 =7,000 6,000

13,000

8,112 – 1,511 =8,000 2,000

6,000

1,415 + 337 =1,400 300

1,700

$78.50 - $31.99 =$80.00 $30.00

$50.00

84,735 + 58,175 =80,000 60,000

140,000

This year, 35,658 people ran in a marathon. Last year, 8,683 fewer people ran. About how many people ran last year?

35,658 – 8,683 =36,000 9,000

27,000 people

There are 152 students in grade 4 and 144 students in grade 5. About how many students are in grade 4 and 5?

152 + 144 =200 100

300 students

Alex sold 86 tickets to a school talent show on Thursday and 103 tickets on Friday. About how many tickets did Alex sell altogether?

86 + 103 =90 100

190 tickets

Estimate 463 + 896. The sum is between which two numbers?

A. 500 and 1,000B. 1,000 and 1,500C. 1,500 and 2,000D. 2,000 and 2,500

500 = 1,400+ 900

Estimate 963 + 751. The sum is between which two numbers?

A. 500 and 1,000B. 1,000 and 1,500C. 1,500 and 2,000D. 2,000 and 2,500

1,000 = 1,800+ 800