Let's practice column subtraction with regrouping (borrowing). First, let's make some flash cards. Gather these materials that you'll use to make flash cards-a black marker, a pair of scissors, and 18 index cards.
Separate the index cards into two groups of nine. Take an index card and write a big number 1 on it. Follow the same procedure for all the other numbers until you reach 9. Once that group is done, do the same with the second group of index cards. Begin with 1 and end with 9. Now you have two sets of flash cards, each set containing numbers from 1 to 9.
You can ask anyone to pick up four numbers for you-two digits from the first set and two digits from the second set. Use the digits to create the numbers for the subtraction problem. Say that the bottom number must be greater than the top number in the ones place (ones column). After arranging the numbers, you can solve the problem.
You can even create your own subtraction problems! Just choose two digits from each set of flash cards. Again, make sure that the bottom number is greater than the top number in the ones place.
Here are sample problems you can work on using your flash cards:
1. 93 - 27 = ?
2. 46 - 19 = ?
3. 78 - 49 = ?
4. 35 - 18 = ?
5. 65 - 36 = ?
Ready to move on to the next lesson?
Place Value and Subtraction
