WHOLE NUMBER SUBTRACTION
BORROWING AND PROBLEM SOLVING
Let’s look at basic computations using subtraction. In subtraction, we find the difference between two numbers. Sometimes we must borrow. To borrow look at the place to the left, the “neighbor” of the column we are subtracting.
Sometimes we encounter a zero in the neighbor’s place when borrowing. In that case, we must go to the next neighbor over to the left to find a value. We may find lots of zeros when we are borrowing where we must look across to find a nonzero number and then borrow until we get back to the place from which we are subtracting.
We will solve word problems where we apply subtraction. Look for key words and read the problem more than once.
Whole Number Subtraction
Estimate the difference, then solve: 5428 - 3764
Estimation: 5000 - 4000 = 1000 The estimated answer is 1000.
Solution: Line up the numbers from right to left so that all place values are in line.  Answer: 5428 – 3764 = 1664
Check: The estimated answer, 1000, is close to 1664.
Check by adding 1664 +3764 5428
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Whole Number Subtraction with Zeros
Estimate the difference, then solve: 4000 - 1582
Estimation: 4000 - 2000 = 2000 The estimated answer is 2000.
Solution: Line up the numbers from right to left so that all place values are in line. Answer: 4000 – 1582 = 2418
Check: The estimated answer, 2000, is close to 2418.
Check by adding 2418 +1582 4000 |
Whole Number Subtraction with Zeros
Estimate the difference, then solve: 7006 - 2379
Estimation: 7000 - 2000 = 5000 The estimated answer is 5000.
Solution: Line up the numbers from right to left so that all place values are in line. Answer: 7006 – 2379 = 4627
Check: The estimated answer, 5000, is close to 4627.
Check by adding 4627 +2379 7006 |
Problem Solving – Subtract
The 4-H club set a goal to earn $500 to cover all the trip expenses. So far they have earned $376. How much more do they need to earn?
The key phrase is "how much more". This is a subtraction problem because the amount of money earned is being compared to the amount of money needed.
$500 - $376 = $124. |
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 Click on the icon to find and practice topics for this unit. |
| Unit 2 Subtraction Worksheet |
| Unit 2 Estimating Differences to the Nearest Thousands Worksheet |
