Multiplying fractions

[Earthlady]

Not sure if science is the best place for this maths question, but here goes.....Can anyone help with a simple explanation of how to multiply fractions so I can help my daughter with her homework?  Rules for addition and subtraction of fractions are also very welcome. At present the sums are very easy (and as my maths skills are generally good I can see the answers easily) but I can't remember how I was taught to do this at school!

[sddsddean]

To multiply fractions, just multiply the numerators and denominators seperately.

EG  2/3    *  5/6

2*5 =10

3*6 = 18

so answer is 10/18 which you can factorise down to 5/9 (by dividing top and bottom by 2)

[Earthlady]

Thankyou - just knew it had to be easy!

[Tweed]

To add or subtract you must first find a common denominator (the number below the line). One way is to multiply them, but is more common to find the smallest. You can multiply (or divide) both numerator and denominator of a fraction by anything other than zero and its value will not change. So the idea is to get the denominators the same and just add the numerators. For example 1/4 + 1/3, smallest common denominator is 12, so multiply 1/4 by 3(top AND bottom), to get 3/12, and 1/3 by 4 (top AND bottom) to get 4/12 add them to get 7/12

[landie]

In addition to the above answers

remember the multiplication sign as 'OF'

that is 1/2 x 1/3 is

1/2 of 1/3 = 1/6

for division 1/2 div by 1/3 is the same as

1/2 x 3/1 = 3/2 or 1+1/2