Regrouping with zero tens (3-digit subtraction)
I explain in detail how to regroup twice when you have zero tens (3-digit subtraction). First we look at a visual model of ones, tens, and hundreds. We have to break down a hundred into 10 tens, and one of the tens in to 10 ones. I also use a model based on place value where each number is written in expanded form (with its parts). These models help children understand what is going on and why it all works.
Regrouping with zero tens, part 2
In the second part, I show how to regroup twice when there are zero tens, using the standard subtraction algorithm.
Lastly for this lesson, I solve a few word problems involving three-digit numbers (addition & subtraction). We also look at a subtraction puzzle with missing numbers.
See also
Regrouping twice in subtraction
Math Mammoth Grade 3 curriculum