Addition and Subtraction of Decimals
1-9
A recent survey shows the amount
of liquid that the average person
consumes per year: 43.7 gal of juice,
37.3 gal of water, 27.3 gal of coffee,
21.1 gal of milk, and 8.1 gal of soda.
How many more gallons of juice,
water, and milk were consumed than
coffee and soda?
To find how many more gallons,
first add, then subtract.
First, find the amount of juice, water, and Next, find the amount of coffee and soda.
milk. Add: 43.737.321.1 Add: 27.3 8.1
11 1
43.7 27.3
37.3 8.1
21.1 35.4
102.1
Then find how many more gallons of juice, water, and
milk were consumed than coffee and soda.
Subtract: 102.1 35.4
So 66.7 more gallons of juice, water, and milk were
consumed than coffee and soda.
Study these examples.
52.9045 63 0.73865.92
12 11
0 52.9045
063 .0000
00 0.7386
00 5.92 00
122.5631
Check. Change the order of the addends.
Add: 5.92 0.7386 63 52.9045 122.5631
?
?
??
9 11
0 10 1 11
1 02.1
3 5.4
6 6.7
0.067 0.0095?
16
5 6 10
0.0 6 7 0
0.0 0 9 5
0.0 5 7 5
0
10
20
30
40
50
Juice Water Coffee
Liquid
Liquid Consumed Yearly
Amount (gal)
Milk Soda
2.0
8206-2_050-051 10/7/07 10:47 AM Page 50