m06, 027

Arithmetic Grade Six

Number chains can also involve a series of subtractions:


	45 - 15 - 10 - 5 - 10 =

In this case you can add up 15 + 10 + 5 + 10 and get 40 and then subtract this sum from 45, like this:


	45 - 15 - 10 - 5 - 10 =
	45 - ( 15 + 10 + 5 + 10 ) =
	45 - 40 =
	ANSWER: 5

Sometimes you wind up with sequences which include subtractions and additions:


	45 - 19 + 24 - 11 + 16 =

Looking for combinations will help you with these problems also. Here's one way you might rearrange this problem to make it easier to solve:


	45 - 19 + 24 - 11 + 16 =
        45 - 19 - 11 + 24 + 16 =
	45 - (19 + 11) + (24 + 16) = 
	45 - 30 + 40 =
	ANSWER: 55