Arithmetic Grade Four

Lesson Eight: Subtraction Review

You will recall that the answer to an addition problem is called the sum. The answer to a subtraction problem is called the difference. Here are some word story problems which involve finding differences: 

   There were 82 children standing in a line. 31 of
   them leave the line. How many children are there remaining
   in the line?
Drawing a picture of a subtraction problem like 82-31 could be done, but it would be more of a bother than it is worth and so we just go straight to solving the number sentence: 
 
    82 - 31 = 51

Here's another word story problem for you to think about: 


   There were 76 donuts on a very large plate. Some people came
   along and ate 31 of them. How many donuts are left?
The number sentence for the story problem looks like this: 
 
    76 - 31 = 45

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