Rounding
Round 57 to the nearest 10
60
Use an area sketch to solve 25 X 34
850
A farmer planted 24 rows of corn, with 36 corn plants in each row. How many corn plants did the farmer plant in total?
864 plants
How many fifties in 250?
5
Use the standard algorithm to solve
47 X 81
3807
Round 71 to the nearest 10
70
Use partial products to solve 82 X 17
80X10= 800
80X7= 560
2X10= 20
2X7= 14
1394
There are 42 classrooms in a school, and each classroom has 25 desks. How many desks are there in the whole school?
,050 desks
If I have 6 fifties, I have...
300
Use the standard algorithm to solve
64 X 90
5760
200
Use partial products to solve 74 X 91
70 x 90= 6300
70 x 1= 70
90 x 4= 360
1 x 4= 4
6734
A bookstore orders 31 boxes of books, and each box contains 28 books. How many books did the bookstore order?
868 books
How many fifties in 150?
3
Use the standard algorithm to solve
25 X 86
2150
Round to the nearest ten to find the most reasonable estimate: 61 x 32
61 rounds to 60
32 rounds to 30
60 x 30 = 1800
Use an area sketch to solve 39 x 29
1131
A zoo has 47 animal enclosures, and each enclosure needs 32 gallons of water each week. How many gallons of water does the zoo use in a week?
1,504 gallons
If I have 9 fifties, I have...
450
Use the standard algorithm to solve
17 x 52
884
Round to the nearest ten to find the most reasonable estimate:78 x 41
78 rounds to 80
41 rounds to 40
80 x 40 = 3200
Use an area sketch to solve 132 x 256
(hint you will need six boxes)
33,792
A stadium has 53 rows of seats, and each row has 44 seats. How many seats are in the stadium?
2,332 seats
How many fifties in 1000?
20
Use the standard algorithm to solve
32 X 55
1760