Answer :

Kytten
4.70, all the others can be simplified to 4.07 by taking away the zeroes after the 7 because they are not significant, The one before the 7 stays because it is significant as it is holding the tenths place value.
ZackFry
You should eliminate all the 0s that appear after the last number greater than 0.  What I mean is that if you have a number, let's say 5.0540, that you remove the last 0 because it doesn't contribute to the actual number.  

Now do it with the numbers for your homework. 
4.07
4.07
4.7
4.07

4.70 is the odd one out.  Therefore, it is not equivalent.