This week we will begin multiplication by 2-digit numbers.  I use a mnemonic device (or memory trick) that I call Tic-Tac-Toe to remind the students of the steps involved.  Many students come back to school after the first night's homework and say, "My mom and dad didn't know anything about tic-tac-toe, so they just showed me the way they learned it."  Tic-tac-toe is not a strategy for multiplying, but just a way of remembering the steps involved.  Basically, after multiplying by the one's place (as we have done for the past week), students will TIC-TAC (cross out the one's place in the bottom number so they know that they are finished multiplying by it), and then TOE (place a zero in the lower level of the addition stage of the equation as a place-holder to remember to start in the ten's place).  Since the game of tic-tac-toe is made of X and O, I use it to help students remember.  See below:
X  15 
Tic-Tac is placing an X over 5 after you mutliply both 4 and 2 by it.
    120  This focuses the child's attention on the 1 for the next step
+ 240 Toe is placing this zero in the one's place

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