Add and subtract rational numbers: word problems
Key notes:
Learn with an example
🎯 Over the weekend, Darren drank 9/10 of a bottle of soda and Tori drank 2/5 of a bottle. How much more soda did Darren drink than Tori?
Simplify your answer and write it as a fraction or as a whole or mixed number.
_____ bottles
Find how much more soda Darren drank by subtracting 2/5 from 9/10.
You can use 10 as the common denominator.
Multiply the numerator and the denominator of 2/5 by 2 to find an equivalent fraction.
2 x 2 / 5 x 2 = 4/10
Now subtract the fractions. Subtract the numerators and keep the denominators the same.
9/10 – 4/10 = 5/10
Write the answer in simplest form. Divide both the numerator and the denominator by 5.
5 ÷ 5 / 10 ÷ 5 = 1/2
Now write the answer.
9/10 – 2/5 = 1/2
Darren drank 1/2 of a bottle more soda than Tori.
🎯 On a school trip, a class travels 4.7 kilometres by train and 9.9 kilometres by bus. How far did the class travel?
______ kilometres
Add the numbers of kilometres. Remember to line up the decimal points.
1
4.7
+9.9
= 14.6
The class travelled 14.6 kilometres.
🎯 At a pizza party, Duncan and his friends drank 3 3/8 bottles of lemon-lime soda and 2 bottles of cola. How much soda did they drink in all?
Simplify your answer and write it as a fraction or as a whole or mixed number.
_______ bottles
Find how much soda they drank in all by adding 3 3/8 and 2.
Add. Remember to add whole numbers to whole numbers and fractions to fractions.
3 3/8 + 2 = 5 3/8
This answer is in simplest form.
Duncan and his friends drank 5 3/8 bottles in all.
Let’s practice!🖊️
