I’m beginning a unit on decimals with my 6th graders shortly, and am looking for ideas on how to introduce tenths, hundredths, comparing, rounding, multiplication, and division. Does anyone have manipulatives that they like that are easy to make or get a hold of? Any good web sites with ideas? I already have blocks comparing fractions/decimals/percents and will be using those, as well as base-10 blocks.
Thanks!
Jenn
Re: Need ideas for teaching decimals
Sorry to take a while getting back on this.
Keep It Simple is the motto. Not a lot of manipulatives, but use well what you have.
Base ten blocks are very good BUT you can lead to huge confusion with the kid who has learned to use one- ten-hundred thousand and has named the blocks in his mind, and now you have re-named the hundred “flat” as 1 and the ten “rod” as 1/10 and the one block as 1/100 — this can throw the kid for a complete loop. Would distress me and I am good at these things; I hate to have the same thing stand for two different ideas, especially if there are no overt clues to which system is being used today.
You really need a smaller set of blocks — don’t know where/if you could buy these, but look around — and they should be distinctly, visually smaller, and at the very least a different colour too. Then having a 1, 1/10, and 1/100 would make sense and be quite different from the whole numbers already established, but similar enough to make connections.
Failing blocks to buy, you (and the kids) could make something out of cardboard with scissors. Make the 1 square noticeably smaller than the 100 flat, and tell the kids it’s a 1 block squished with a roller. Use coloured cardboard to readily distinguish from white cuisenaire 1 blocks. You could make a ditto, print out a bunch for the class to cut out with say two 1 big squares, twenty 1/10 rods, and twenty 1/100 squares, and have them keep the results in envelopes. The 1/100 would get to be quite teeny, but that is kind of the point.
Another useful thing is money. I actually get a baggie full of pennies, dimes, and dollars, and work with the kids physically handling it (practical only if you can store safely of course.) Some people use cardboard models of money to avoid the theft issue — can be bought through some stores, I think possibly Scholar’s Choice. No nickels and quarters at first, only the tenths and hundredths. Since we write money as decimals anyway this system is often used to introduce decimals, but you have to be sure to carry on to thousandths and to show other uses of decimals as well.
Sorry to take a while getting back on this.
Keep It Simple is the motto. Not a lot of manipulatives, but use well what you have.
Base ten blocks are very good BUT you can lead to huge confusion with the kid who has learned to use one- ten-hundred thousand and has named the blocks in his mind, and now you have re-named the hundred “flat” as 1 and the ten “rod” as 1/10 and the one block as 1/100 — this can throw the kid for a complete loop. Would distress me and I am good at these things; I hate to have the same thing stand for two different ideas, especially if there are no overt clues to which system is being used today.
You really need a smaller set of blocks — don’t know where/if you could buy these, but look around — and they should be distinctly, visually smaller, and at the very least a different colour too. Then having a 1, 1/10, and 1/100 would make sense and be quite different from the whole numbers already established, but similar enough to make connections.
Failing blocks to buy, you (and the kids) could make something out of cardboard with scissors. Make the 1 square noticeably smaller than the 100 flat, and tell the kids it’s a 1 block squished with a roller. Use coloured cardboard to readily distinguish from white cuisenaire 1 blocks. You could make a ditto, print out a bunch for the class to cut out with say two 1 big squares, twenty 1/10 rods, and twenty 1/100 squares, and have them keep the results in envelopes. The 1/100 would get to be quite teeny, but that is kind of the point.
Another useful thing is money. I actually get a baggie full of pennies, dimes, and dollars, and work with the kids physically handling it (practical only if you can store safely of course.) Some people use cardboard models of money to avoid the theft issue — can be bought through some stores, I think possibly Scholar’s Choice. No nickels and quarters at first, only the tenths and hundredths. Since we write money as decimals anyway this system is often used to introduce decimals, but you have to be sure to carry on to thousandths and to show other uses of decimals as well.