REASONING: if you know that 9x20 = 180, how can you use this to find 9x24? explain your strategy
Twenty-four is only four more than twenty. So you only really need to figure out the answer for nine times four, which is thirty-six. Then just add your two sums together. 180 + 36 = 216.
Just do 9x4 which equals 36, and add that to 180, which equals 216.