4 + 8 = 12

So now we have to put the 12 in between the 4 and 8 but don’t do this: 4128 as that is wrong...

 

First, do this: Place the 2 from the twelve in between the 4 and 8 giving 428.

 

Now we need to input the 1 from the twelve into our answer also, and to do this just add the one from 12 to the 4 of 428 giving 528!

 

Ok, one more 74 X 11 7 (put the 1 from the right of 11 in) and 4 then add the 1 from the left of 11 to the 7