Multiplication problems usually give information for one unit and ask information for many units. For example, you may be given an average distance for one hour and asked for a distance for six hours. You may be given the price for one item and asked the price for 96 items.

Remember that multiplication is fast addition of equal amounts. Key words for addition may also point to multiplication.

Key words that point to multiplication:

• altogether
• combined
• in all
• total
• the average is
• product
• how many?
• how much?
• each

Exercise 1

Do these problems by following the five problem-solving steps. Remember to circle the information and underline what is being asked. Be sure to write down your estimation before you find the actual solution. Check your work using the answer key at the end of the exercise.

1. Maria spent $151 a month to ride to work. How much did it cost her to ride to work for the whole year? (1 year = 12 months)
2. Fred travels 121 km a day on his delivery route. How far does he travel in 5 working days?
3. Manuel buys 340 L of gas a month. In 6 months, how many litres of gas does Manual buy?
4. An apartment building has 16 apartments, each rented for $870 a month. What is the total monthly rental income from this building?
5. A farmer sells potatoes at $53 per 50 kg sack. How much will he get for 75 sacks?
6. Bob is paid $12 per hour. If he worked 39 hours last week and 24 hours this week, how much did he earn for the two weeks? (two operations)
7. It costs $35260 per working day to run the factory. How much does it cost to run this factory for a month of 23 working days?
8. The train has an average speed of 75 km an hour. How far does this train travel in 14 hours?
9. Lee’s sports car averages 18 km per litre. How far can she drive on 12 L of gasoline?
10. Frank bought a used car and paid for it over 15 months. He made 15 monthly payments of $325 each. How much did he pay?

Answers to Exercise 1

1. $1812
2. 605 km
3. 2040 L
4. $13920
5. $3975
6. 63hours, $756
7. $810, 980
8. 1050 km
9. 216 km
10. $4875

Topic D: Self-Test

Mark  /8    Aim  6/8

Solve these problems. Show all your work. Give yourself one mark for the correct method and one mark for the correct answer.

a. A freight train has 70 cars. Each car can hold 22680 kilograms of cargo. How much cargo can the train hold in all?

b. The highway distance between Fernie and Edmonton is 621 kilometres. How many kilometres will a bus travel in 68 trips from Fernie to Edmonton?

c. A tanker truck made 275 trips in one year. The truck hauled 23,800 litres each time. How many litres did the truck haul during the year?

d. The college cafeteria hopes to serve 425 people each day. Estimate how many meals will be served if the cafeteria is open 175 days.

Answers to Topic D Self-Test

1. 1587600 kilograms
2. 42228 kilometres
3. 6545500 litres
4. 400 × 200 = 80000 meals