Arithmetic Grade Five

Lesson Fifty-five: Decimal Multiplication and Parentheses


Figure out the answers to these two problems:

	.4 + .5 x .7 - .3 = 

	(.4 + .5) x (.7 - .3) =

Recall that parentheses make a big difference in how we solve problems. Also recall that we perform multiplication before addition or subtraction. With this in mind you will realize that in the first example we multiply .5 x .7 first and then add .4 and subtract .3. In the second example we add .4 + .5 and we subtract .7 - .3 and then we multiply this difference and the previous sum.

	.4 + .5 x .7 - .3 = .45

	(.4 + .5) x (.7 - .3) = .36

Here's another example:
 
	.3 - .2 * .5 + .2 = .4

	(.3 - .2) * (.5 + .4) = .09

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