# multiplying fractions

• Sep 11th 2009, 07:39 AM
andyboy179
multiplying fractions
this is my question:
$\displaystyle 3\frac{1}{2}$ x $\displaystyle 1\frac{1}{4}$

i need to know how to do that queston but could you please ut workings out!!! thanks
• Sep 11th 2009, 07:46 AM
Quote:

Originally Posted by andyboy179
this is my question:
$\displaystyle 3\frac{1}{2}$ x $\displaystyle 1\frac{1}{4}$

i need to know how to do that queston but could you please ut workings out!!! thanks

change these fractions into improper fraction first

7/2 x 5/4 = 35/8
• Sep 11th 2009, 07:56 AM
andyboy179
Quote:

change these fractions into improper fraction first

7/2 x 5/4 = 35/8

how did you get 7/2 x 5/4, did u do this to get it:
3x2 =6+1=7 then use the same demominator= 7/2
1x4=4+1=5 then use the same demominator =5/4

and by 5/4 do u mean $\displaystyle \frac{5}{4}$ ??
• Sep 11th 2009, 02:23 PM
HallsofIvy
Quote:

Originally Posted by andyboy179
how did you get 7/2 x 5/4, did u do this to get it:
3x2 =6+1=7 then use the same demominator= 7/2
1x4=4+1=5 then use the same demominator =5/4

and by 5/4 do u mean $\displaystyle \frac{5}{4}$ ??

Specifically, what he did was write 3 as 6/2 so that 3+ 1/2= 6/2 + 1/2= 7/2 and write 1 as 4/4 so that 1+ 1/4= 4/4+ 1/4= 5/4. And, yes, 5/4 is just a simpler way of writing $\displaystyle \frac{5}{4}$

As to what you wrote, yes, 6+1= 7 but no, 3x2 is not equal to 6+ 1!