Mental Math
40 x 20
800
Please solve and show your work: 15 x 36
540
Estimate the product - show your work: 52 x 134
50 x 130 = 6,500
What is the answer to a multiplication question called?
Sound travels about 310 m in a second. If you see a lightening flash and head thunder 12 seconds later, how far away is the lightening?
310 x 12 = 3,720
The lightening is 3,720m away.
300 x 1,000
300,000
Please solve and show your work: 32 x 56
1,792
Estimate the product - show your work: 109 x 98
110 x 100 = 11,000
When you are estimating, you are checking to see if your answer is ________________.
Reasonable
A carton holds 8 eggs. How many cartons do you need to hold 1800 eggs?
1800 / 8 = 225
225 cartons are needed to hold 1800 eggs.
21,000 / 300
70
Please solve and show your work: 68 x 234
15, 912
Estimate the product - show your work: 3333 / 8 =
3330 / 10 = 333
When dividing numbers, the number you are dividing by is called the _____________.
Divisor
A tour company expects to transport 2,500 people to a Football game. How many 9-passenger vans do they need?
2,500 / 9 = 277 with a remainder of 7 so 278 vans are needed to transport 2,500 people.
56,000 / 80
700
Please solve and show your work: 3461 / 2
1730 R1
Is this answer reasonable? Explain.
6245 / 52 = 120
If we round 6,245 to 6,250 and 52 to 50 our estimate would be 6,250 / 50 = 125 so 120 is a reasonable answer.
When you are dividing, the larger number that you are splitting up is called the ______________.
Dividend
The distance between two bus depots is 378km. A bus makes two round trips twice a week. What is the total number of km travelled by the bus each year?
1 round trip: 378 x 2 = 756
The bus makes two round trips, twice a week: 756 x 4 = 3,024
3,024 is the total number of km the bus travels in a week and there are 52 weeks in a year so 3,024 x 52 = 157, 248km travelled in the year.
480,000 / 1,200
400
Please solve and show your work: 2189 / 6
364 R5
Is this answer reasonable? Explain.
962 / 7 = 190
If we round 962 to 960 and 7 to 10 our estimate is 960 / 10 = 96 so 190 is not reasonable.
What is the answer of a division problem called?
The Quotient.
Rotherglen has decided to make Christmas 76 sweaters for those in need. We need 12 buttons for each sweater. A package of 4 buttons costs $3. What is the cost of all the buttons?
76 sweaters x 12 buttons for each = 912 buttons in total
912 / 4 pack = 228 packs of buttons needed
Each pack costs $3, therefore 228 x 3 = $684
It would cost $684 for all the buttons we need to make 76 sweaters.