Add zeros after the numerator and move the decimal as many places as you added 0s to get a workable division. To estimate 5/7 divide 50/7 = a little bit more than 7 so your answer will be about 0.7 or 0.71.
You can estimate fractions by quickly rounding to the nearest one half. For example 6 and 7/9 + 5 and 4/7 would round to 7 + 5.5. This method is quick and accurate.
