| Tasha and Kaitlyn love watermelon! Their mom just brought one home |
from the store and cut it up for them to share. Tasha ate 4 pieces and
Kaitlyn ate 1 piece.
Hint: If it helps, draw the pieces if watermelon in the space below.
Write the math equation: ______________________
How many pieces did the girls eat? _______
Tuesday, 6 December 2011
Impress your friends and give them a little practice with their math times tables with this mathematical magic trick.
Tell your friend to pick their favorite number between 1 and 100, but don't tell you what it is!
Note: If your friends are children, have them pick a number between 1 and 9 so they are able to do the next steps. If you're doing this with mom and dad, you can tease them and make them pick REALLY big numbers so they have to work hard at the math. They'll be very surprised when you come back with the answer so quickly!
Have them multiply their number by 2.
Have them multiply their number by 5.
Have them tell you the answer they've come up with.
Drop the zero from the answer they gave you and tell them what their number was!
Favorite number = 5
5 x 2 = 10
10 x 5 = 50
50 --- drop the zero = 5!
Favorite number = 32
32 x 2 = 64
64 x 5 = 320
320 --- drop the zero = 32!
Impress your friends and give them a little practice using a calculator with this mathematical magic trick.
You could also do this without a calculator for kids learning long multiplication problems, but it's a BIG job.
Tell your friend to pick their favorite number between 1 and 9, but don't tell you what it is!
Tell them that through the magic of their calculator, you will show them your number.
Using the calculator, have them multiply their number by 9.
Now have them multiply that number by 12,345,679. (1 thru 9, skipping the 8)
TAH DAH... The calculator shows them their number -- 9 times!
Favorite number = 5
5 x 9 = 45
45 x 12345679 = 555,555,555
Favorite number = 9
9 x 9 = 81
81 x 12345679 = 999,999,999