To ask for your help with a fractions question??

[raspberryriot]

I hope you don't think AIBU to ask for help with this maths homework question? Just posting here for traffic. My DD (Year 6) has been set some really difficult maths homework and I promised I'd help her with the workings out but not just give her the answer. I was terrible at Maths at school but just managed to scrape my O' Level. Anyway the question is:

Write the missing number as represented by x.

160
= 0.2

x

I have found out via the internet that the answer is 800 (it's a Level 6 SATs question) but I don't know how to work it out? Am I just plain stupid?

I will be writing a note to the teacher to explain that DD found this too difficult but I'm curious to know how you do it so I can help her?

I reckon it's something to do with Cross Multiplication and Algebraic Fraction Equations but my brain has glazed over....

Clear workings out would be much appreciated!!!

Thanks in advance.

I know - very heavy day D'oh

I did mention I was a dork

Perhaps it's easiet if you remember that whenever you have
a / b = c
you can just swap b and c, so
a / c = b

(This is just a shortcut for multiplying both sides by b / c ).

i.e.
160 / x = 0.2
so
160 / 0.2 = x

How many 0.2s in 160? Or how many fifths in 160? There are 5 fifths in 1 So 5x160=800

This makes sense!

Thanks nannyOgg, that was my non-maths explanation

Just do the inverse.
Inverse of divide is times.