3.OA.A.3
Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
3.OA.B.6
Understand division as an unknown-factor problem. For example, find 32 ÷ 8 by finding the number that makes 32 when multiplied by 8.
Solve division problems by relating to multiplication. For example, find 16 / 2 by finding the number that makes 16 when multiplied by 2. Start with arrays and equal groups, then move away from them. Then relate multiplication to division via word problems. For example, 5 * 7 = 35 and 7 * 5 = 35 are related to 35 / 7 = 5 and 35 / 5 = 7.