A fraction is usually split into two parts: the first part is the number on top, called the numerator; and the second part is the number on the bottom, called the denominator. These are both separated by a line called the “divisor line”. We can use the division method help to solve this question: to get a decimal, simply divide the numerator 3150 by the denominator 55 (which you can enter in any calculator):
3150 (numerator) ÷ 55 (denominator) = 57.27
And finally, you get 57.27 as your answer when you convert 56 70/55 (or 3150/55) to a decimal.