Page 862 - Algebra 1

Decimal Operations
Skills Bank Lesson 2
To add or subtract decimals, align the numbers at their decimal points. Then perform the operation the same way as adding or subtracting whole numbers.
Adding and Subtracting Decimals
Example
1
a. Find the sum of 24.5 and 1.235.
SOLUTION
b. Find the difference of 36.762 and 4.2.
SOLUTION
24.5 + 1.235 24.500
36.762 - 4.2 36.762
Write the problem vertically.
+ 1.235 Align the decimal points. - 4.200
____ ____ 25.735 32.562
To multiply decimals, multiply first. Then place the decimal so that the product has the same number of decimal places as the total number of decimal places in the two factors. To divide decimals, multiply the divisor and the dividend by a power of 10 in order to make the divisor a natural number. Then divide as with whole numbers.
Multiplying and Dividing Decimals
a. Find the product of 1.25 and 2.7. SOLUTION
1.25 × 2.7
1.25 Write the problem vertically. ×2.7
Example
2
___
3.375 Since the factors have a total of 3 decimal places, there should be 3 decimal places in the product.
b. Find the quotient of 3.72 and 0.3. SOLUTION
3.72 ÷ 0.3
1 2.4
0 . 3 3 . 7 2 M u l t i p l y t h e d i v i s o r a n d d i v i d e n d b y 1 0 s o t h e d i v i s o r i s a n a t u r a l n u m b e r .
Skills Bank Practice
a. Find the sum of 19.3 and 24.54.
c. Find the product of 4.28 and 0.216.
Simplify.
e. 176.4-23.72 f. 24.6+18.76
b. Find the difference of 55.755 and 30.93. d. Find the quotient of 0.756 and 0.06.
g. 84.7×6.2 h. 7.95÷1.5
Skills Bank 847
SKILLS BANK