# Talk

## Maths help... algebra

(6 Posts)
CinnamonPretzel Sat 20-Aug-11 16:21:16

Quick question for any maths bods: -

= 5/2 + (-2)
= 5/2 - 2
= 5/2 - 4/2
= 1/2

why has it gone from 2 into 4/2?

Help appreciated.. and yes I should speak to my tutor but trying to catch up

winnybella Sat 20-Aug-11 16:24:58

because you need a common denominator for 5/2 and 2- so 2 is 2/1 multiplied by 2 so becomes 4/2. Now you can do 5/2 (which is 2.5) - 4/2 (which is 2) and you get 1/2 i.e. 0.5.

poppyknot Sat 20-Aug-11 16:25:16

So you can do the subtraction I think.

In addition and subtraction of fractions the denominator has to be the same in both numbers....

(Vague mists of time maths memory looming up from the depths)

spanieleyes Sat 20-Aug-11 16:31:55

You could, of course, have changed the 5/2 into 2 and a 1/2 and then subtracted the 2 from the 2 leaving just the 1/2!

CinnamonPretzel Sat 20-Aug-11 16:36:04

Thats very helpful. It brings back the hazey memory from some previous units on fractions etc. I didn't want to just move on in the questions without understanding why - so thank you for helping

CinnamonPretzel Sat 20-Aug-11 16:40:49

Yes Spaniel, that would have been my working - I've never been any good at fractions but slowly getting there. Strange how as an adult I'm picking up things easier - or maybe its just that they explain things in a way you can understand without making you feel small and stupid now

Join the discussion

Registering is free, easy, and means you can join in the discussion, get discounts, win prizes and lots more.

Register now