What is the expanded notation for 2,909? numbers may be used once, more than once, or not at all. (2x what) + (9x what) + (9xwhat) fill the what’s with the correct answer

(2 x 1,000) + (9 x 100) + (9 x 1)
Always check the place values by looking at the number (2,909) and you can figure out what number to multiply it by. Guess and check if you can’t recognize it right away.

The length of what is left would be 1 1/2 feet long.