in which of the following expressions can we replace each of occurance of the number 8 by the same positive integer (other than 8) and obtained the same result
1)(8+8)÷8+8
2)8×(8+8)÷8
3)8+8-8+8
4)(8+8-8)÷8
Answers
Answer:
Here are some interesting links:
A Reading list of Tricky Math Books, most of which I have used for this site.
Learn about the original computer: The Abacus
Play a Math-Chase Game-- for one or two players. (If you're using Netscape, Do Not Scroll down the page while this loads.
Play at Shoot Balls.
Play Flippo 24.
Test your knowledge of the multiplication tables.
Try your hand at estimation.
Explore Geometryin a fun and interactive way.
Try the Tower of Hanoi Puzzle.
See what a Spriographis.
See what a Mandelbrot setis.
If you want more math challenges try the new PBS MATHLINE MATH CHALLENGESsite. Try it, you'll like it. (But remember we were first.)
Magic Addition Trick #1
Amaze the peons with this one. It's simple. It's effective. It gets them every time.
Ask your mark to pick three (3) different numbersbetween 1 and 9.
Tell him or her (or her or him) to write the three numbers down next to each other, largest first and smallest last, to form a single 3-digit number. Tell him/her not to tell you what the numbers are.
Next have her or him form a new 3-digit number by reversing the digits, putting the smallest first and the largest last. And write this number right underneath the first number.
Now have him or her subtract the lower (and smaller) 3-digit number from the upper (and larger) 3-digit number. Tell them not to tell you what the result is.
Now you have a choice of wrap-ups:
Ask your friend to add up the three digits of the number that results from subtracting the smaller from the larger 3-digit number. Then amaze him or her by teling them what the sum of those three numbers is. The sum of the three digit answer will always be 18!
Tell your friend that if she or he will tell you what the first OR last digit of the answer is, you will tell her or him what the other two digits are. This is possible because the middle digit will always be 9, and the other two digits will always sum to 9! So to get the digit other than the middle one (which is 9) and other than the digit that your friend tells you, just subtract the digit your friend tells you from 9, and that is the unknown digit.