What is cool, unusual, bizarre, interesting, inviting - in multiplication? Make your list of five things. Here is mine:

1 - Behold the fractal power of powers!


2 - I can count to 512 on my fingers! Can you? Never trust the man who can count to 1024! (hint: think binary)

3 - My favorite model of multiplication (combinations) is excellent for making chimeras for Halloween:


4 - My favorite multiplication craft: the mirror book.


5 - Googol is a cool multiplication word. It is 10 multiplied by itself 100 times. Here:
10,​000,000,000,​000,000,000,​000,000,000,​000, 000,000,​000,000,000,​000,000,000,​000,000, 000,​000,000,000,​000,000,000,​000,000,000,​000,000,000

No, I did not type it - I copied it from Wikipedia. You are welcome to check if they got the zeroes right, or if somebody quietly removed or added some.

Here are some things I find kind of interesting about multiplying and dividing:
1. Multiplying by zero always equals zero. No matter how long the problem is, if it includes multiplying by zero, the answer is zero.
Ex. 23,000,158,096*394,761*823,569,247*0*960,387,358,824.7374=0
2. When you multiply two negative numbers you get a positive number.
3. Prime numbers are still being found. In September a prime digit with 13 million digits was discovered. (They used computers to find it)

BrianH wrote:

3. Prime numbers are still being found. In September a prime digit with 13 million digits was discovered. (They used computers to find it)

Oops, that should say a prime number with 13 million digits was discovered.

in the nine multiplication if you add the digets of the product it will equal nine.
so if it is 9x7 it =63

1. Mirrored numbers 71 turns into 17. What is the equation?

x=71 y=17

x/10=7.1
floor (x/10)=7
10*floor(x/10)=70
x-10*floor(x/10)=71-10*7=1

[x-10*floor(x/10)]*10 + floor (x/10)=17

x=91
9.1
9
90
1
19

James

1. When you multiply by many-digit numbers, you have "added zeros" in there for place value.
Benjamin

2. Powers of ten