To check multiplication of single digits by longer numbers with playing cards:
We’re going to use what I call “numbers crunching” to check. That is the same as using the nines-remainders. You do know how to get the nines-remainder of a number, don’t you? It’s very simple, but it takes a bit of explaining.
It also pays to know why checking with nines-remainders works. Both of those things are beyond the scope of this article, but I’m working on a booklet and a video about how to check your answers for all of the basic operations of math using “number crunching”. There are lots of tips and shortcuts that make this method absolutely simple and effective. Let me know if you’re interested by using the “Contact” box near the upper right hand corner of this page.
(This video will be re-edited and uploaded by the end of Wednesday, April 30)
If you know about crunching, you’ll be interested to know that practicing with cards like this is perfect for checking with crunching. It turns out that if you crunch all the digits from zero to nine, you get a crunch number of 0.
Continue reading Practicing and Checking Multiplication With Playing Cards (2) →
Math Mojo has got some surprises for you. New lessons on how to improve your basic math skills, and videos! Professor Homunculus is getting his Video Mojo workin’ to bring you some great new stuff.
The first set of videos will be about how to practice multiplication using playing cards. So grab a deck of cards and [...]
A girl recently asked:
“I need help learning multiplication. Can you help me learn to multiply?”
Professor Homunculus replied:
I have lots of questions to ask you, but first, here is something you can do right away to help you learn multiplication by 2, 3 and 4:
Get out a deck of cards. Make sure they are all (52) there. [...]
Do you want to understand and be able to multiply in order to:
a) help you (or your child) with life in general and the education that counts, or
b) just help you (or your child) pass the next math test?
If your answer was b, you just saved yourself some time and effort for the next few minutes. You don’t have to read any further. But you’d be costing yourself (or your child) years of frustration. Passing a little (or big, standardized) test is just jumping through an artificial, meaningless, hoop. You don’t have to be a slave to the school system.
If you really need to beat the system, you need to game it. You need to learn math much, much better than they teach it to you in public schools. Then their tests will be a joke, and you will blow them away without being intimidated. But if you just want to learn enough to get through the next test, brother, you are digging your own educational grave.
Continue reading Understanding Multiplication →
