Unit 5: Using Decimals in Real Life
Topic B: Decimal Word Problems
Key Words
Spend a few minutes reviewing the key words that will help you identify addition, subtraction, multiplication and division word problems.
Some key words that point to addition include:
Some key words that point to subtraction include:
- difference
- balance
- minus
- amount left
- subtracted from
- decreased by
- reduced by
- taken away
- less
- compare
Some key words which point to multiplication include:
Some key words which point to division include:
- separated
- split
- cut
- shared
- What is the cost per…?
- unit price
- What is the distance per…?
- average (speed, cost, weight, time)
Read over some of the problems that you have done in each unit to remind yourself of the patterns to expect for different operations.
Steps for Solving Word Problems
Carefully review the five steps to use when solving problems:
Step 1: Question
- Read the problem carefully.
- What is the question being asked?
- Does the problem have two parts?
- Draw a picture to help you see the problem described.
Step 2: Information
- What information is necessary to solve the problem?
- Often you are given extra numbers and information that are not needed.
- Keep the question (destination) in mind.
- Circle the information you need.
- Write that information on the picture you drew.
Step 3: Operation
- Decide what arithmetic operation to use.
- Do you need to add, subtract, multiply, or divide?
- If the problem has two parts, decide what operation you need to do for each part.
- Key words often point to the operation needed.
- Drawing a diagram or sketch is always helpful.
- Write an equation (a number sentence).
Step 4: Estimate
- Estimate the answer to the problem.
- Round the numbers so you can work with them quickly.
- Use the operation you chose in Step 3 and come to a quick answer.
- Does this estimated answer make sense?
- Does it answer the question of the problem?
- Think carefully before you do Step 5.
Step 5: Solve
- Solve the problem using the actual numbers.
- Check your arithmetic.
- Compare your answer in Step 4 to your estimate from Step 3.
- Think again about the question. Does your solution make sense?
- When you write your answer, include the units.
For example: 3 dozen eggs, 7.5 kilometres, 68 people
Exercise 1
- The total weight of an A.T.V. is 293.937 kg. If a hunter who weighs 62.142 kg carried an extra 68.39 kg, how much would her entire A.T.V. weigh when loaded?
- Estimation:
- Actual solution:
- Answer:
- The Head Start shuttle bus drives a route that is 12.73 km long. It drives this route 5 times a day. How many kilometres does the bus drive in one day?
- Estimation:
- Actual solution:
- Answer:
- Mary bought a TV. She made a down payment of $75.00 and then made monthly payments of $56.19 for twelve months. How much did she pay for the TV altogether?
- Estimation:
- Actual solution:
- Answer:
- The total number of employee hours to be paid on the weekly payroll for the Dry