Question

Kylie has an idea for how to calculate 23 23. She says,

"Twenty times 20 is 400, and 3 times 3 is 9;, so 23 23 should be 400 plus 9, which is 409."
What is wrong with Kylie's method? Don't just start over in a different way and don't compute 23-23
directly and compare the answer with Kylie's, work with Kylie's idea. Shade the large square below,
which consists of 23 rows with 23 small squares in each row, to help you explain your answer.

Answer 1

Don't just start over in a different way, work with Kylie's idea. Use the large square below, which consists of 23 rows with 23; Question: 1. Kylie has an idea for how to calculate 23-23. She says, Twenty times 20 is 400, and 3 times 3 is 9, so 23-23 should be 400 plus 9, which is 409.

Explanation: