5th Grade Multiplication Unit 1

5th Grade 4 x 2

100

2021 x 32

64,672

200

2305 x 31

71,455

300

1,062 x 51

54,162

400

5,325 x 25

133,125

500

Calinda sold 4,329 boxes of chocolates; she sold them for $12 a box.  How much money did she make?

$51,948

5th Grade Factoring

100

List all the factors of 5

1, 5

200

List all the factors of 8

1, 2, 4, 8

300

List all the factors of 9.

1, 3, 9

400

List all the factors of 16.

***DAILY DOUBLE***

1, 2, 4, 8, 16

500

List all the factors of 28.

1, 2, 4, 7, 14, 28

5th Grade 3 x 2

100

525 x 25 = 

13,125

200

433 x 42

18,186

300

468 x 30

Also thought of as:  468 x 3 x 10

14,040

400

645 x 64

41,280

500

Sam's Club sold 707 Lego sets on Black Friday.  Each set had 83 mystery pieces.  How many mystery pieces where sold at Sam's Club on Black Friday?

***DAILY DOUBLE***

58,681 mystery pieces in all

5th Grade 2 x 2

100

53 x 17

901

200

34 x 60

Also can be thought of as: 34 x 6 x 10

2,040

300

53 x 18 

954

400

67 x 94 

6,298

500

Peter grew 87 peach trees on his property.  Each peach tree grew 55 plump, perfect peaches.  How many peaches did Peter harvest in all?

4,785 plump, perfect peaches

5th Grade Math Rounding

100

Why should you use rounding along with the traditional multiplication algorithm?

You can see if your actual answer is close to your estimate.  If you are far off, you know you have probably made a mistake and can fix it before the teacher does.

200

What would you round each number to?

46 x 62

50 x 60

300

What would you round these numbers to?

542 x 73

500 x 70

400

Alexandria did the following calculations:

69 x 75 is like 70 x 70 so my answer should be close to 490.  She then solved for 69 x 75 and got 5,175.  Where did she make her mistake?

She made two mistakes in her estimate.  She rounded 75 down to 70 and it should have been rounded to 80 and 70 x 70 equals 4,900 not 490.

500

Estimate first and then solve:  432 x 45

400 x 50 = 20,000

432 x 45 = 19,440