SECTION 1-WHOLE NUMBER ARITHMETIC

WORKING WITH PARENTHESES

We have already seen examples where two arithmetic operators were used

when multiplying 575 by 5 at one point we wrote 7 x 5 = 35 and 35 + the carried 2 = 37
When dividing 87535 by 287, we ended up subtracting the product of 3 and 287 (861) from 875

Here are the same two problems written with parentheses

The first problem could be written as (7 x 5 ) + 2
The parentheses says to first multiply 7 x 5, and then add 2 to this product.
The second problem could be written as 871 - (287 x 3)
The parentheses says to first multiply 287 x 3, and then subtract this product from 871

What if we had the expression (7 x 3 ) - 2
The parentheses would say first multiply 7 x 3 (getting a product of 21), and then subtract 2 (getting an answer of 19)

Here is another expression using parentheses

145 - (34 + 11)

The parentheses tell us to first add 34 and 11, and then subtract this total from 145.
34 + 11 = 45 and 145 - 45 = 100

I'll show this to you one more time

(79 - 7) / 9

The parentheses is telling us subtract 7 from 79, and then divide the resulting difference by 9.
79 - 7 = 72 and 72 / 9 = 8

It is now time for you to practice problems that use parentheses.
The important thing to remember is always do what is in the parentheses first

Click on the "generate a parentheses problem" button to see your exercise. Place your answer in the text box and then click the "check my answer" button. The computer will then tell you whether or not your answer is correct.

After you complete the problem, you can generate another problem by first clicking the "reset button" and then clicking the "generate a parentheses problem" button. Continue as many times as you wish, and then:

All text, images, and source code c2003 Martin Selditch.