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    add/subt fractions
    By roo

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    In addition to what the previous poster mentioned, here's something to try. I have a large fraction circle (mine's a pizza) on the board. I usually start with this example: Bobby ate 1/2 of his pizza for dinner. Later he ate 1/2 of his pizza for a midnight snack. How could we figure out how much pizza he ate IN ALL? Someone will usually tell me to add, so I'll show the problem 1/2 +1/2 on the board. I'll ask if anyone thinks they can tell me the sum. Someone always tells me 2/4. So then I show them what 2/4 looks like. We discuss that 1/2+1/2 CAN'T be 2/4 because that simply equals 1/2. We decide that when you add halves to halves you get halves. (I usually make it simple and give an example like what is one monkey plus one monkey? It doesn't equal 2 elephants, it equals 2 monkeys! Think of denominators the same way.) So 1/2+1/2 =2/2 or 1 whole. We do lots of examples with common denominators before even thinking about having to find common denominators on our own.


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