Multiply by Multiples 10, 100 & 1,000
Mental Math: Round to Estimate Products
The Distributive Property
We say "Partial Products"
We think "Place Value"
We think "Place Value"
Possible Test Questions
100
3 x 70=
210
100
6 x 112=
About 600
100
Use Distributive to solve (box method)
5 x 921=
(5 x900) + (5x20) + (5x1) =
4,500 + 100 + 5 = 4,601
100
Solve using Partial Products
227 x 3 =
(rewrite it)
681
100
In one week, the Pancake House sells 602 pancakes and 482 waffles.
How many pancakes and waffles are sold in 5 weeks?
5,420
200
6 x 400=
2,400
200
4 x 2,610=
About 12,000
200
Use Distributive to solve (box method)
4 x 352=
(4 x 300) + (4 x 50) + (4 x 2) =
1,200 + 200 + 8 = 1,408
200
solve using partial products
1,165 x 7 =
(rewrite it)
8,155
200
600
30
27
300
8 x 6,000=
48,000
300
3 x 287=
Round 287 to ____
3 x ______= ______
3 x 300= 900
300
Use Distributive Property to solve
6 x 310= 6 (300 x ____)
= (6 x ____) + (____ x 10)
= _______ + _______
= ___________
1,860
300
Solve using partial products
4,826 x 6 =
28,956
300
Mrs. Heim is selling boxes of cards in boxes of 30 and boxes of 60. If she sells 5 boxes of 60, how many trading cards did Mrs. Heim sell?
300 trading cards
400
7,000 x 4=
28,000
400
5 x 1,240 = 9,200
Is this reasonable?
Round 1,240 to ______.
5 x _____= _______.
5 x 1,000= 5,000
9,200 is not reasonable.
400
Use Distributive Property to solve
4 x 1,554 = _________
6,216
400
use partial products to solve
2,459 x 7 =
17,213
400
Select all the partial products for 7 x 532.
a. 14
b. 35
c. 210
d. 3,500
e. 4,000
a. 14
b. 210
c. 3,500
500
The Mississippi River is about 8 times the length of the Hudson River. If the Hudson River is about 300 miles long, about how many miles is the Missippi River?
8 x 300= m
m= 2,400
About 2,400 miles
500
Elle estimates the product of 211 and 6 is 1,800. Is this estimate reasonable? Explain.
No.
211 should be rounded to 200 and then multiplied by 6 to get 1,200.
200 x 6= 1,200
500
A lodge at a state park has 49 rooms. Up to 5 people can stay in each room. What is the maximum number of people who can at stay the lodge at one time?
______ toes?
245 people
500
Tommy spent $1,856 on 4 computers each. Use partial products to find out how much money Tommy spent in total.
$7,424
500
How can the Distributive Property be used to find
7 × 391?
7 × 391 = 7 × (300 + 90 + 1)
7 × 391 = (7 × 300) + (7 × 90) + (7 × 1)
7 × 391 = 2,100 + 630 + 7