DECIMALS 



15. Skill in the use of decimals in everyday life depends 

 mainly upon the ability to multiply and divide instantly 

 by 10 or some power of 10. This skill may be acquired by 

 practice exercises in multiplying and dividing decimals by 

 10, by moving the decimal point one place to the right when 

 multiplying, and one place to the left when dividing. Divi- 

 sion may be indicated by the sign (-;-) or by writing the 

 dividend above the divisor in the form of a common frac- 

 tion ; thus, 432 -j- 24, or 



432 

 '24 * 



ORAL EXERCISE 



1. Multiply 387.96 by 10; by 100; by 1000. 



2. Multiply .0167 by 10; by 100; by 1000. 



3. Divide 379.4 by 10; by 100. 



4. Divide 753.21 by 10 ; by 100 ; by 1000. 



5. Divide .8 by 10; by 100. 



6. Divide .25 by 10; by 100. 



7. Multiply both dividend and divisor in - - by 10. 



^4 



or rrcy 



8. Multiply both dividend and divisor in ' by 10; 



by 100. 



1.728 



9. Multiply both dividend and divisor in by 10; 



by 100. 



6 2575 



10. Multiply both dividend and divisor in ' by 10; 



by 100 ; by 1000. 



11. State the effect on the quotient when both the divi- 

 dend and the divisor are multiplied by the same number. 



13 



