Читать книгу Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online) - Mark Zegarelli - Страница 34

As with addition, stacked subtraction allows you to subtract larger numbers systematically.

For example, to subtract , stack the numbers as follows:

Now, as with addition, start in the ones’ column and work right to left, this time subtracting each pair of numbers in the column, and place each result below the line:

So .

In most cases when you subtract, the calculation will involve borrowing at least one digit from one column to the next.

For example, suppose you want to subtract :

To begin, you want to subtract in the ones’ column. However, 3 is less than 4, so to subtract, you need to borrow 1 from the tens’ column, changing the 5 to 4. Then, this 1 that you borrowed is worth 10 in the ones’ column, so add it to the 3, changing it to 13:

Now, you can subtract , and place this result in the ones’ column below the line:

Next, you want to subtract in the tens’ column. Again, you need to borrow 1 from the column to the left, changing 8 to 7, and adding 10 to the 4, making it 14:

Now, you can subtract , placing 8 in the tens’ column below the line:

To complete the problem, subtract in the hundreds’ column:

Therefore, .