Knowing your three times table really helps with your mental arithmetic, which will be handy in everyday life. Use the array to help you work this out. 3 lots of 7 (or 7 lots of 3) is 21.
Build up the three/six/nine times table; using different structures/interpretations of multiplication and division, solve problems related to these tables; explore connections between the three, six ...
the times table has something for everyone. Multiplication is the art of adding groups of things efficiently. Imagine having three baskets of apples, with each basket holding four apples.