Arrays and Multiplying by 10 and 100
Draw an array for 5 x 10 and solve!
50 (with array)
Solve 300 x 4
1,200
SHOW how you can break apart to multiply 4 x 36 and solve!
4 x 30 = 120
4 x 6 = 24
120 + 24 = 144
SHOW how you can use compensation to solve for 5 x 17
5 x 20 = 100
100 - 15 = 85
SHOW how you can estimate the problem 6 x 125
6 x 100 = 600
Draw an array for 1 x 100 and solve!
100 (with array)
Solve 600 x 7
4,200
SHOW how you can break apart to multiply 3 x 19 and solve!
3 x 10 = 30
3 x 9 = 27
30 +27 = 57
SHOW how you can use compensation to solve for 7 x 29
7 x 30 = 210
210-7 = 203
SHOW how you can estimate the problem 7 x 314
7 x 300 = 2,100
Draw an array for 6 x 10 and solve!
60 (with array)
Solve 800 x 5
4,000
SHOW how you can break apart to multiply 6 x 23 and solve!
6 x 20 = 120
6 x 3 = 18
120 + 18 = 138
SHOW how you can use compensation to solve for 4 x 23
4 x 20 = 80
80 + 12 = 92
SHOW how you can estimate the problem 6 x 609
6 x 600 = 3,600
Draw an array for 3 x 100 and solve!
300 (with array)
Last year, the fourth graders at Summit School collected 500 cans of food for the food drive. This year's fourth graders want to collect 3 times as any cans. How many cans do this year's fourth graders hope to collect?
1,500 cans
SHOW how you can break apart to multiply 5 x 143 and solve!
5 x 100 = 500
5 x 40 = 200
5 x 3 = 15
500 + 200 + 15 = 715
SHOW how you can use compensation to solve for 3 x 195
3 x 200 = 600
600 - 15 = 585
SHOW how you can estimate the problem 719 x 5
700 x 5 = 3,500
Draw an array for 4 x 100 and solve!
400 (with array)
A fourth grader breathes about 90 gallons of air per hour. Shana, a fourth grader, arrives at school at 8:00 a.m. and leaves at 3:00 p.m. How many gallons of air does she breathe at school?
630 gallons
SHOW how you can break apart to multiply 4 x 462 and solve!
4 x 400 = 1,600
4 x 60 = 240
4 x 2 = 8
1,600 + 240 + 8 = 1,848
SHOW how you can use compensation to solve for 5 x 109
5 x 100 = 500
500 + 45 = 545
SHOW how you can estimate the problem 2 x 863
2 x 900 = 1,800