Show:
multiplying by 10 and 100
Breaking apart to multiply
partial products
mental math
Estimate
100
3 x 70 =
210
100
Break apart the factor to find your product. 4 x 36 =
4 x 30 = 120, 4 x 6 = 24, 120 + 24 = 144
100
What are the partial products of 4 x 16 ?
40 and 24
100
7 x 28 =
196
100
Use rounding to estimate your product. 41 x 9 =
40 x 9 = 360
200
9 x 60 =
540
200
Break apart the factor to find your product. 5 x 75 =
5 x 70 = 350, 5 x 5 = 25, 350 + 25 = 375
200
What are the partial products of 7 x 45?
280 and 35
200
61 x 8 =
488
200
Use rounding to estimate your product. 6 x 291 =
6 x 300 = 1,800
300
5 x 60 =
300
300
Break apart the factor to find your product. 5 x 143 =
5 x 100= 100, 5 x 40 = 200, 5 x 3 = 15, 100 + 200 + 15 = 315
300
What are the partial products of 3 x 246?
600, 120 and 18
300
4 x 23 =
92
300
Use rounding to estimate your product. 394 x 2 =
400 x 2 = 800
400
300 x 4 =
1,200
400
Break apart the factor to find your product. 5 x 389 =
5 x 300= 1,500, 5 x 80= 400, 5 x 9 = 45, 1,500 + 80 + 45 = 1,625
400
What are the partial products of 6 x 790?
4,200 and 540
400
Ashley and 3 friends bought tickets to a show. The cost of each ticket was 43 dollars. How much did the tickets cost in all?
$172
400
Use rounding to estimate your product. 54 x 8 =
50 x 8 = 400
500
How many zeros will there be in the product for 5 x 200?
5 x 200 = 1,000; 3 zeros
500
Break apart factor to find your product. 4 x 462 =
4 x 400 = 1,600, 4 x 60= 240, 4 x 2 = 8, 1,600 + 240 + 8 = 1,848
500
What are the partial products of 9 x 704?
6,300 and 36
500
A store clerk is stacking soup cans on shelves. If he puts 110 cans on each shelf, how many cans will be on 4 shelves?
440
500
Ellie estimated that the product of 211 and 6 is 1,800. is the estimate reasonable? Why or why not?
The product is not reasonable because 211 should be rounded to 200 to get 1,200.