What's a rational number between 7.7 and 7.9?

It would simply be 7.8, because its also rational. Its also between 7.7 and 7.8.

A rational number is a number that can be expressed as the relationship between two integers. Fractions and decimals will either repeat or end. An example is 5. Maybe 7. 53573 is an example as well. So is 5/1, because 5 and 1 are both integers. so is 7.5, because 7 and 5 are both integers, and it ends (the numbers after the decimal doesn't keep going). Your answer is 7.8, because it ends.