Let's solve each of the four word problems step by step, identifying whether we need to use
addition or
subtraction, and explaining the reasoning.
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Problem 1:
> Janet is reading a book with 80 pages. On Monday she read 39 pages. On Tuesday she read 33 pages. How many pages does Janet have left to read?
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Step-by-step Solution:
- Total pages in the book:
80
- Pages read on Monday:
39
- Pages read on Tuesday:
33
- Total pages read so far:
$ 39 + 33 = 72 $
- Pages left to read:
$ 80 - 72 = 8 $
✔ Answer: Janet has
8 pages left to read.
➡️ This problem involves
adding the pages read (combining groups), then
subtracting from the total.
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Problem 2:
> 145 people boarded a plane in Houston. In San Antonio, 78 people got off and another 55 people got on. How many people were on the plane when it left San Antonio?
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Step-by-step Solution:
- Initial number of people:
145
- People who got off in San Antonio:
78 → subtract
- People who got on:
55 → add
So:
$ 145 - 78 = 67 $ (after people got off)
$ 67 + 55 = 122 $
✔ Answer: There were
122 people on the plane when it left San Antonio.
➡️ This problem uses
subtraction (people leaving) and
addition (people boarding).
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Problem 3:
> Maverick earned $750 at his job in the past office and another $450 last week. He spent $935 on a new car. How much money does Maverick have left?
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Step-by-step Solution:
- Earnings:
$ 750 + 450 = 1,200 $
- Amount spent:
$935
- Money left:
$ 1,200 - 935 = 265 $
✔ Answer: Maverick has
$265 left.
➡️ This problem combines
addition (total earnings) and
subtraction (money spent).
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Problem 4:
> Kathryn walked 4,350 more steps than Kim. Kim walked 3,728 steps. How many steps did Kim and Kathryn walk combined?
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Step-by-step Solution:
- Kim’s steps:
3,728
- Kathryn walked
4,350 more than Kim:
$ 3,728 + 4,350 = 8,078 $
- Combined steps:
$ 3,728 + 8,078 = 11,806 $
✔ Answer: Together, Kim and Kathryn walked
11,806 steps.
➡️ This problem uses
addition to find Kathryn’s steps and again to combine both totals.
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✔ Final Answers:
1.
8 pages left to read
2.
122 people on the plane
3.
$265 left
4.
11,806 steps combined
All problems involve a mix of
addition and subtraction, as expected in multi-step word problems. The key is to break down each step carefully and identify what operation is needed at each stage.
Parent Tip: Review the logic above to help your child master the concept of addition and subtraction word problems worksheet 4th grade.
