Andres
secondary
student

how do i convert a decimal into a fraction?
and how do i solve this problem?
18 + -12/9

 

Hi Andres,

You can think of the place value system and the values of the places to the right of the decimal. For example

3.1 is 3 and one tenth, that is 3 and 1/10 

thus

3.1 = 3 + 1/10  = 30/10 +  1/10  = 31/10  

Likewise

3.134 = 3 + 1/10 + 3/100 + 4/1000 = 3 + 100/1000 + 30/1000+ 4/1000 = 3000/1000 + 134/1000 = 3134/1000

At this point you might be able to simplify the fraction. In this case both the numerator and denominator are divisible by 2 so

3.134 = 3134/1000 = 1567/500

For 18 + -12/9 I would first simplify 12/9 since both the numerator and denominator are divisible by 3. Thus

12/9 = 4/3

Hence

18 + - 12/9 = 18 + - 4/3

But 18 = 54/3 and hence

18 + - 12/9 = 18 + - 4/3 = 54/3 + - 4/3 = 54/3 - 4/3 = 50/3

Penny