– 4007 - DISCRETE MATH - math tricks! You all work with numbers, here are some tricks to teach your kids. Everyone has a struggle learning their multiplication tables, and remembering them. I especially have problems remembering the multiples of nine.
-------------- 4007
- DISCRETE MATH - math tricks!
- To my son and
daughter the math teachers.
- To my other
daughter the accountant
-
- The digits of
multiples of 9 always sum to a multiple of 9:
-
----------------- 2 *
9 =
18 --------- 1 + 8
= 9
----------------- 3*
9 =
27 --------- 2 + 7
= 9
----------------- 4 *
9 =
36 --------- 3 + 6
= 9
-
----------------- 7 *
9 =
63 --------- 6 + 3
= 9
----------------- 8 *
9 =
72 --------- 7 + 2
= 9
----------------- 9 *
9 =
81 --------- 8 + 1
= 9
-
----------------- 123
* 9 =
1,107 --------- 1 + 1 +7
= 9
-
----------------- 581
* 9 =
5,229 --------- 5 + 2 +2 +9
= 18 = 2 * 9
-
- How many feet in
a 9 miles?
-
-----------------
5,280 * 9 = 47,520
--------- 4 + 7 +5 +2
= 18 = 2 *
9
-
- Why does this
always work?
-
- It is a law in
Discrete Math. “Discrete Math” is
digital math. The most common math is
“Continuous Math”, or analog math.
Continuous math deals with calculus, pi, continuous graphs. Discrete Math only deals with integers. It is
used in computer math that works with only “1’s” and “zeros“
-
- Add up all the
numbers form 1 to “n“
-
- The sum is = n^2
/ 2 + n / 2
-
- The sum of 1 to
5 = 5^2 / 2 + 5/2 = (25
+ 5) / 2 = 15.
-
- The sum of 1 to
100 =
100^2 / 2 + 100 / 2 = 5000
+ 50 = 5050
-
- If you only add up
the odd numbers from 1 to “n” the answer
is = n^2
-
- The sum of 1+3+5+7
= 4^2 = 16
-
- That is Discrete
Math. “String Theory” is another new
math. If you want to learn about String
Theory request the Review.
-
- A deck of 52, how
many pairs can be dealt in a poker game?
A quick formula will tell you 1,098,240.
Well, how many hands are there?
2,598,960. So you have about 4
chances out of 10 to get dealt a pair.
42% chance. Learning math can
be fun.
-
May 16, 2023 DISCRETE
MATH - math tricks! 1211 4007
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--------------------- --- Tuesday, May 16, 2023
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