Home Addition Subtraction Multiplication Place Value Divisibility
Michele's Math, Place Value
by K. Michele Smith
I made up a story for preschoolers and use it to teach place value and subtraction with borrowing for older children.
I start young children comparing fingers, hands and toes. To introduce the concept of place value to young children (I consider first grade young for this), ask how many fingers she has, then how many toes, then how many fingers you have, etc.
Now ask if she has seen anyone with 11 fingers, or 9 (I actually had one child say she had an aunt with 11 toes - imagine my surprise!!) lol. Whether your child knows anyone with more or fewer fingers, you can still ask if this is the "usual" amount. The object is to help the child finalize the concept that "10" is the usual number of fingers and toes for people. Now just put your hands together, like in prayer or clapping, and call that "one set of fingers with zero extra's" and demonstrate writing that:
you will end up with the number ten - writing the 1 and saying "one whole set of fingers", then the 0 and saying "and zero extra's".
Now you can show her that 1 whole set of fingers and one whole set of toes is 2 whole sets with zero extra's, or 20.
From there we play a little game with our hands. Have her put both her hands flat on the table, making sure she understands that her ten fingers is 1 whole set with zero extra's. Now put one of your hands on the table near hers, with a couple (two?) fingers out. With the other hand you can write the number as you explain it: Together you have 1 whole set and 2 extra's - 12.
You can make all the teen's this way. If you play on the floor you can add your feet for more sets, creating numbers in the 20's, 30's, etc. More children may get confusing at first so I wouldn't suggest a group effort to make large numbers. Most children get the concept after a few minutes of this, and transfer the idea to paper.
Oh, to practice making groups of ten's, use pop beads or lego's - things that stick together - and make piles to organize - count out groups of ten, link them together, write them as 10 or 20 or whatever, then make sure there are some "left over" for numbers like 13, 24, etc. Then practice writing the number you *create*.
Many children get confused about "borrowing" because they aren't thinking through *why* they are doing it. This is where place value lessons come in handy. First, remember that each digit is "10" of the previous digits, all bundled up. Each 10 is ten singles, each 100 is 10 10's, each thousand is 10 100's, etc.
When you borrow, it's because you don't have enough to subtract from, so you have to run _next door_ (never anywhere else) and borrow a _BAG_ of digits - each bag has 10 in it, so when you get back, you pour out your bag of digits (or jellybeans or whatever), to add to what you had to start with.
Rule: you can NEVER borrow a bag of digits from anyone but your left hand neighbor, never more. If your neighbor has none to give you, then _he_ goes to _his_ next door neighbor, gets a bag and pours them out, then and only then does he have 10 from which you can borrow your bag.
402
- 125
Ok, you can't take 5 jellybeans if you only have 2 on the table, so you run next door to borrow a bag. But your next door neighbor (0) doesn't have any, so the 0 runs next door to the 4 and borrows a box, pours out the box of 10 bags (changes the 0 to 10) and then the 2 can borrow one of those 10 (leaving 9 in the middle). The 2 goes home and pours out it's bag of 10, giving him 12 - now you can subtract 5. Since the 0 already borrowed a bag and gave the 2 one, there are 9 there, so you can subtract 2, etc.
Can you see this? It's much easier to go through when you can write, cross out and point as you go! Hope it makes sense.
This is fun to practice with jellybeans or M&M's, but it takes a LOT of them to make the piles of 10. I don't get into hundreds and thousands, though
For more ideas from Michele, check Valder Phonics
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