Difference between 100 and 89.5

Vertically align numbers with Larger Number on top:

1 0 0 . 0
8 9 . 5

Subtract using place value:

Hundreds Tens Ones Tenths
9 9
0 10 10 10
100 1 0 0 . 0
89.5 8 9 . 5
Difference 1 0 . 5

Column traversal from right to left
Tenths column:

  • Since 0 is less than 5, we have to borrow 1 from the Ones column
  • As a result, 0 becomes 10, and 10 − 5 = 5
  • The 0 in the Ones column becomes 9 after borrowing 1 from its regrouped value of 10

Ones column:

  • 9 − 9 = 0
  • The 0 in the Tens column became 9 after 1 was borrowed from its regrouped value of 10 for the purpose of regrouping the 0 in the Ones column

Tens column:

  • 9 − 8 = 1
  • Because it was the first nonzero digit to the left of the 0 in the Tenths column, the 1 in the Hundreds column became 0 after 1 was borrowed for the purpose of regrouping the 0 in the Tens column (borrowing across 0s)

Hundreds column:

  • 0 − 0 = 0

Note: Leading zero is dropped

9 9
0 10 10 10
1 0 0 . 0
8 9 . 5
1 0 . 5
Therefore, the Difference between 100 and 89.5 is 10.5

Check computation by comparing Larger Number and the Sum of Smaller Number and Difference:

1 1 1
8 9 . 5
1 0 . 5
1 0 0 . 0

Sum of Smaller Number and Difference = 100 (trailing zero is dropped)
Sum of Smaller Number and Difference = Larger Number (100 = 100) ✓

The solution above and other related solutions were provided by the Difference Between Two Numbers Application.

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