If there is seven thousand earthquakes in christchurch and 7/10ths are below a magnitude 6 then how many are above a magnitude 6

Great answer anon,

another way to do it is

$${\frac{{\mathtt{3}}}{{\mathtt{10}}}}{\mathtt{\,\times\,}}{\mathtt{7\,000}} = {\mathtt{2\,100}}$$

Can you see why ?

If anyone wants me to explain then please ask :)

The answer is 2100

$${\frac{{\mathtt{7}}}{{\mathtt{10}}}}{\mathtt{\,\times\,}}{\mathtt{7\,000}} = {\mathtt{4\,900}}$$ , 1) This is the first step: to find 7/10ths of 7000

$${\mathtt{7\,000}}{\mathtt{\,-\,}}{\mathtt{4\,900}} = {\mathtt{2\,100}}$$     , 2) Then Subract