Question

reasoning: if you know that 9 x 20 = 180, how can you use this to find 9 x 24? explain your strategy.

Answer 1

9 × 24 = 9 × ( 20 + 4 ) = 9 × 20 + 9 × 4 = 180 + 36 = 216 ;

Answer 2

9 * 20 = 180

24 has 4 more than that, so multiply 9 to 4 and add it to 180.

9 * 4 = 36

180 + 36 = 216

So 9 * 24 = 216