7 can be written 7.000... as many zeroes as you like. Now divide by 8 as if there was no decimal point. We get 875, but when we write 875 over the top of 7.000 the 8 sits over the 0 next to the decimal point so that's where we put it in the answer: 0.875. We put the zero at the beginning so that we don't accidentally lose the decimal point because of its smallness. The zero protects it.