4.NF.A.1

Explain why a fraction *a*/*b* is equivalent to a fraction (*n* × *a*)/(*n* × *b*) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.

Understand a/b = (n * a)/(n * b) for any choice of n. Use this idea to solve equations using equivalent fractions. For example, x/3 = 4/3, x = ___, or 4/12 = 1/x, x = ___.