Subtraction to 1,000
Subtraction to 1,000 without crossing tens or hundreds
Subtraction to 1,000 without crossing tens or hundreds
Subtraction to 1,000 using standard algorithm with regrouping 
Subtraction to 1,000 using standard algorithm with regrouping
Subtraction to 1,000 splitting the subtrahend with regrouping
Subtraction to 1,000 splitting the subtrahend with regrouping
Subtraction through 100 regrouping hundreds as tens
