Subtract from 200 and from numbers with zeros in the tens place

In this lesson, students apply their understanding of place value and the subtraction algorithm to subtract numbers within 200. They use place-value disk drmawings on a place-value chart. Students then model 1 hundred as 9 tens and 10 ones and practice counting to 100 both ways. Next, they model the decomposition of a hundred either in two steps (as 10 tens then decomposing 1 ten as 10 ones) or one step (as 9 tens and 10 ones) as they represent subtractions from 200.