80% of 70 is 56. There are different ways to calculate this, but one common method is to multiply 70 by 80/100, which gives 56. Another way is to set up a proportion where x is the unknown value we want to find, and 80 is the percentage we are given: 80/100 = x/70. Solving for x, we get x = 56. Therefore, 80% of 70 is 56.