To round a decimal first you need to find what you need to round it by. Tenths place, hundredths place, thousandths place, and then you need to find the number to the right of it. If you are rounding to the hundredths place in 0.687, than you would look at 8 and see if it is above or below 5. If above, 0.687 turns into 0.7. If below it turns into 0.6. In this case it is higher so 0.7.