7.07 Story problems with adding and subtracting like fractions
Are you ready?
Do you remember how to add and subtract fractions?
Find the value of $\frac{4}{8}-\frac{1}{8}$48−18.
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Sometimes a problem is given as a story or description, and might have the fractions given using words or a mix of words and numbers.
When faced with a story problem, start by determining what value we are trying to solve for - this will often be in the last sentence. After that, look back through the rest of the story to find:
- any numbers/values that we know
- a keyword that will tell us what operation to use
Let's look at an example, and highlight the key terms: "Glen is walking along a hiking trail, and passes a campsite $5$5 sixths of a mile along. Later he reaches another campsite, a further $8$8 sixths of a mile along the trail. How far has Glen traveled in total when he reaches the second campsite?"
The keywords "in total" tells us that we want to find a sum of the two fractions.
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Question
Hermione throws a ball and it hits the ground $7$7 eighths of a meter away from her. The ball then rolls a further $3$3 eighths of a meter away and stops.
Complete the number sentence for how far the ball is away from Hermione.
Total distance$=$=$\frac{\editable{}}{8}+\frac{\editable{}}{8}$8+8 meters
Find the answer to the number sentence.
When we have a word problem, we need to think about the story and use the keywords to work out which operators to use. Some words that we may find in a story could be:
| addition | subtraction |
|---|---|
| more | less |
| in total | remaining |
| plus | take away |
| sum | difference |