Unit 4: Multiplication
Topic C: Word Problems
Learning multiplication facts is very important. Once you know them all, you can use them to solve word problems.
Words such as product, altogether and in all tell you may need to multiply the numbers. Look for these words when reading and underline them before trying to solve a problem. Circle the information that is given.
Example: Mr. Wong rides his bicycle 6 kilometres every day. How far will he ride altogether in 9 days? Mr Wong rides his bicycle 6 kilometres every day. How far will he ride altogether in 9 days?
You have circled 6 kilometres and 9 days. This is the information you will use to find the answer.
You have underlined How far will he ride. These words tell you to multiply.
6 kilometres × 9 days= 54
Mr. Wong will ride 54 kilometres in 9 days.
Exercise One
Solve each of the following word problems. Be sure to underline the words that tell you to multiply. Circle the information that is given. Have your instructor check your underlining and circling .
- There are 5 rows of mailboxes in an apartment building. There are 7 mailboxes in each row. How many mailboxes are there in all?
- At the grocery store, there are 8 cans of corn in each row. There are 6 rows of corn. How many cans of corn are there altogether?
- There are 7 days in a week. How many days are there in 4 weeks?
Answers to Exercise One
- 35 mailboxes
- 48 cans
- 28 days
Area
Area means the surface that is inside a shape. The units of measure of area are always square units (meaning having both length and width).
Rectangle
To find the area of a rectangle, multiply length × width.
Example A
To find the area of the rectangle, multiply length × width.
Area = length × width
Area = 8 metres × 3 metres
Area = 24 square metres
Example B
To find the area of the rectangle, multiply length × width.
Area = length × width
Area = 4 centimetres × 7 centimetres
Area = 28 square centimetres
Square
To find the area of a square, multiply side × side.
Example C
To find the area of the square, multiply side × side.
Area = side × side
Area = 9 metres × 9 metres
Area = 81 square metres
Exercise Two
Find the area of each shape. Be sure to include the units of measure in your answer. Check your work using the answer key at the end of the exercise.
- A floor is 8 metres long and 4 metres wide. What is the area of the floor? (Hint: Draw a picture.)
Answers to Exercise Two
- 2 square metres
- 3 square metres
- 100 square centimetres
- 32 square metres
Topic C: Self-Test
Mark /8 Aim 7/8
- Solve each of the following word problems. (8 marks) Be sure to include the unit of measure in your answer. (2 marks each). Be sure to circle information and underline what is being asked.
- Diego puts 6 apples into each bag. How many apples are there in 4 bags?
- Alain wants to walk up 6 flights of stairs. There are 10 steps in each flight. How many steps will he have to walk up altogether?
- In the metric system, 10 millimetres equals 1 centimetre. How many millimetres are there in 100 centimetres? (Hint: Multiply the number of centimeters by 10.)
- Find the area of the picture.
Answers to Topic C Self-Test
-
- 24 apples
- 60 steps
- 1000 millimetres
- 15 square metres