hw+t3w7

Take 60. Divide 60 by 2. Add your telephone number digits. Subtract 25. Multiply by 3. Subtract 15. Multiply by 2. Divide by 6. The answer is your telephone number. Check out the answer key to see this expressed in an equation.
 * 1) Did you know that if you multiply 111,111,111 X 111,111,111 that the answer is consecutive? Try it and then check the answer key to see what happens.
 * 2) Did you know that if you take your phone number through a series of algebraic steps in an equation, that you come out with the same phone number when you are done? Try it:
 * 1) Do you want to know a numerical magic trick? See if you can figure out this game: Take a number, any number. Multiply by 2. Add 8. Divide by 2. Subtract the number you started with. Your answer is 4.

What's the trick? After you have thought about it for awhile, check out the answer key. But don't cheat! Think first!

MIND READER: These instructions tell you how to do a cool card trick that's guaranteed to make you look like a mind reader. Try it with a friend, then spring it on some unsuspecting victims—like your parents! ||  ||||  || A deck of cards A friend A pencil and paper ||  || Shuffle the deck. That way your victim—oops, your friend—knows you haven't done anything weird to the deck of cards.
 * [[image:http://www.exploratorium.edu/math_explorer/images/instructions.gif width="102" height="20" caption="Instructions"]]
 * [[image:http://www.exploratorium.edu/math_explorer/images/test4.gif width="140" caption="What Do I Need?"]]
 * [[image:http://www.exploratorium.edu/math_explorer/images/stitle_whatDoIDo.gif caption="What Do I Do?"]] ||
 * [[image:http://www.exploratorium.edu/math_explorer/images/step1.gif width="50" height="20" caption="Step 1"]]

||||  || Ask your friend to choose any card from 1 (ace) to 9, but not a 10, jack, queen, or king. Tell them not to show it to you, but to memorize the number on it.
 * [[image:http://www.exploratorium.edu/math_explorer/images/step2.gif width="50" height="20" caption="Step 2"]]

|| Tell your friend to put his or her card on the table, face down.
 * [[image:http://www.exploratorium.edu/math_explorer/images/step3.gif width="50" height="20" caption="Step 3"]]

|| Now you take a card from the shuffled deck. Choose a card with a number from 1 (ace) to 9. Don't choose a 10, a jack, a queen, or a king. Don't show the card to your friend.
 * [[image:http://www.exploratorium.edu/math_explorer/images/step4.gif width="50" height="20" caption="Step 4"]]

|||| || Memorize the number on the card, then lay the card face down on the table on the right side of your friend’s card. Be sure that your card is to the right of your friend’s card.
 * [[image:http://www.exploratorium.edu/math_explorer/images/step5.gif width="50" height="20" caption="Step 5"]]

|| Now comes the "magic" part. Give your friend the paper and pencil so that he or she can do some math. Now tell your friend to do the following things—without showing you the answers:
 * [[image:http://www.exploratorium.edu/math_explorer/images/step6.gif width="50" height="20" caption="Step 6"]]

||||  ||  Double the value of the card. Add 2 to that number. Multiply the result by 5. |||||| <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">Example: //** <span style="color: rgb(51, 51, 51); font-family: Verdana,Arial,Helvetica,sans-serif;"> Suppose they have the 3 of hearts:
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">What you tell your friend to do: //**

<span style="font-family: Verdana,Arial,Helvetica,sans-serif;">3 * 2 = 6 6 + 2 = 8

8 * 5 = 40 ||  || <span style="font-family: Verdana,Arial,Helvetica,sans-serif; color: rgb(255, 153, 51);"> ||   || <span style="font-family: Verdana,Arial,Helvetica,sans-serif; color: rgb(255, 153, 51);"> || So far, your friend has been doing all the math. In this step, you have to do a little math in your head. Take the number of the card you chose. (You remember what it is, don't you?) Then do the following:
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">[[image:http://www.exploratorium.edu/math_explorer/images/step7.gif width="50" height="20" caption="Step 7"]]

||||  ||
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">What you do: //**

Subtract the number of your card from 10. || <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">Example: //** Suppose your number is 8

10 - 8 = 2 ||  || Now it’s your friend’s turn again.
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">[[image:http://www.exploratorium.edu/math_explorer/images/step8.gif width="50" height="20" caption="Step 8"]]

||||  || Tell your friend your answer from Step 7. Have your friend subtract that from the number he or she got after doing all the math in Step 6.
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">What you tell your friend to do: //**

Ask your friend to tell you what number he or she got after doing all that math. || <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">**//<span style="color: rgb(255, 153, 51);">Example //**

40 - 2 = 38

Our friend said 38 || <span style="font-family: Verdana,Arial,Helvetica,sans-serif;"> ||

Here’s the magic part. Flip over your friend's card on the table, and then your own. There will be the two digits of the number your friend said. Enjoy the shocked look on your friend's face!
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">[[image:http://www.exploratorium.edu/math_explorer/images/step9.gif width="50" height="20" caption="Step 9"]]

||||  || But wait! Suppose your friend came up with a different number. Mutter something like, "I know the magic worked—so let’s check your math." Check the math—and you will get the number that’s on the cards.
 * ^  ||^   || [[image:http://www.exploratorium.edu/math_explorer/images/mind_reader_03.gif width="180" height="114"]] ||   ||
 * <span style="font-family: Verdana,Arial,Helvetica,sans-serif;">[[image:http://www.exploratorium.edu/math_explorer/images/step10.gif width="60" height="20" caption="Step 10"]]

||  ||   ||
 * || <span style="display: block; text-align: center; font-family: Verdana,Arial,Helvetica,sans-serif;">**<span style="color: rgb(0, 204, 255);">Why Does This Trick Work? ** ||