Unit 6 Review (10/24)

Estimate Products of Multi-Digit Factors (6-1)

100

209 x 4 = ?

Estimate the product

200 x 4 = 800

(Round 209 down to 200)

*If students answered "836" accept answer

200

583 x 7 = ?

Estimate the product

600 x 7 = 4,200

Round 583 up to 600

*if student answered "4,081" accept answer

300

8,102 x 5 = ?

Estimate the product

8,000 x 5 = 40,000

Round 8,102 down to 8,000

*If student answered "40,510" accept answer

400

3,099 x 3 = ?

Estimate the product

3,000 x 3 = 9,000

Round 3,099 down to 3,000

*if student answered "9,297" accept answer

500

49,952 x 9 = ?

Estimate the product

50,000 x 9 = 450,000

Round 49,952 up to 50,000

*if student answered "449,568" accept answer

Multiply Multi-Digits With 1-Digit Factors (6-2)

100

3 x 62 = ?

*Remember to decompose numbers that more than 1-digit**

186

(60 + 2)=62

3 x 60 = 180     3 x 2 = 6       180+6=186

200

228 x 4 = ?

912

(200 + 20 + 8)=228

4x200=800  4x20=80  4x8=32     800+80+32=912

300

532 x 3 = ?

1,596

(500+30+2)=532

3x500=1,500  3x30=90  3x2=6

1,500 + 90 + 6 = 1,596

400

434 x 7 = ?

3,038

(400+30+4)=434

7x400= 2,800  7x30= 210  7x4=28

2,800 + 210 + 28 = 3,038

500

3,265 x 3 = ?

9,795

(3,000+200+60+5)= 3,265

3x3,000= 9,000  3x200= 600  3x60= 180  3x5= 15

9,000 + 600 + 180 + 15 = 9,795

Distributive Property (6-3)

100

4 x 63 = ?

252

(4x60)= 240       (4x3)= 12

             240+12 = 252

200

7 x 135 = ?

945

(7x100)=700  (7x30)= 210  (7x5)= 35

              700 + 210 + 35 = 945

300

4 x 333 = ?

1,332

(4x300)= 1,200  (4x30)= 120  (4x3)= 12

            1,200 + 120 + 12 = 1,332

400

6 x 607 = ?

3,642

(6x600)= 3,600  (6x7)= 42

     3,600 + 42 = 3,642

500

8 x 2,619 = ?

20,952

(8x2,000)=16,000  (8x600)=4,800  (8x10)=80

(8x9)= 72

16,000 + 4,800 + 80 + 72 = 20,952

Multiply Two Multiples of 10 (6-4)

100

10 x 30 = ?

300

(1x3)=3

Include 0s after = 300

200

50 x 80 = ?

4,000

(5x8)=40

Include 0s afterwards = 4,000

300

20 x 30 = ?

600

(2x3)=6

*include 0s afterwards = 600

400

70 x 30 = ?

2,100

(7x3)= 21

*Include 0s afterwards = 2,100

500

90 x 90 = ?

8,100

(9x9)=81

*include 0s afterwards = 8,100

Multiply Two-Digit Factors (6-5)

100

13 x 25 = ?

325

13=(10 + 3)   25=(20 + 5)

10x20=200  10x5=50  3x20=60  3x5=15

200 + 50 + 60 +15 = 325

200

22 x 44 = ?

968

22=(20+2)  44=(40+4)

20x40= 800  20x4= 80  2x40=80  2x4= 8

800 + 80 + 80 + 8 = 968

300

49 x 53 = ?

2,597

49=(40 + 9)  53=(50 + 3)

40x50= 2,000  40x3= 120  9x50=450  9x3= 27

2,000 + 120 + 450 + 27 = 2,597

400

78 x 87 = ?

6,786

78=(70 + 8)   87=(80 + 7)

70x80= 5,600  70x7= 490  8x80=640  8x7= 56

5,600 + 490 + 640 + 56 = 6,786

500

194 x 28 = ?

5,432

194=(100 + 90 + 4)     28=(20 + 8)

*100x20= 2,000 | 100x8= 800  |  90x20= 1,800

90x8= 720  |  4x20= 80  |  4x8= 32*

2,000 + 800 + 1,800 + 720 + 80 + 32 = 5,342