Hey! I thought it would be helpful to start a thread on mental calculation and specially a series of tips and tricks on how to make them faster, as it is, I've come to understand, the very basis of Poker Maths. This applies to everyone playing live at least, you need to be pretty much able to make quick calculations in your head in order to maximize your victories.

I've been re searching on the topic and I found two really good ways of quickly multiply two digit numbers in your head that I wasn't aware of (I personally am quite good in maths and can understand all the hard stuff, fairly quick, but sharp and fast, on-the-spot mental calculations are an area that I want to develop even further and bring them to a higher level).

If anyone knows good tips to quickly do sums, subtractions, multiplications, divisions, ratios, percentages, etc, in your head, feel free to share it here.

So, I've come across two basic strategies (bear in mind that you need to train these if you have a little trouble reaching the results as it is, and I assure you that you'll become better and sharper over time, you'll see massive improvement in just the first week and it only goes up from there.)

• 1st strategy: This first strategy works for two digit numbers multiplying by each other.

Example: 34*72=_ _ _?

What you do here is adding three spaces mentally or bear in mid that you'll fill three spaces. (It can reach more than 3).

Then you multiply the first digit of the first number by the first digit of the second number, so: 3*7=21

So, you have: 34*72= 21_ _

Then you multiply the second digit of the first number by the second digit of the second number, so: 4*2=8

You now get: 34*72=21_8

Now you're going to multiply the 2nd digit of the 1st number by the 1st digit of the 2nd number and the 1st digit of the 1st number by the 2nd digit of the 2nd number, and you're gonna add the results: (4*7)+(3*2)=28+6= (If you want a simple way to do it in your head just do 30+6 and then subtract 2)= 34

Now you just add the 3 of the 34 to the 1 that was there, just like a you'd do on an algorithm and you have the result: 34*72=2448

• 2nd strategy: This second strategy is all about the base numbers and using them in our favour, so let's start out with using 10 as the base number as it is the easiest one.

Y'all can use this rule for numbers that are fairly close to 10, for example:

13*18=?

So, what we do here is basically see how much each number is above or below ten, so 13 is +3 above ten and 18 is +8 above ten.

So, we have +3 +8

13 * 18=?

Now we're going to add either the 3 to the 18 or the 8 to the 13 (because it's easier we'll add the 3 to the 18 which is 21, adding 8 to 13 would also be 21 but it's easier to reach that conclusion by adding 3 to 18)

Which will give off: +3 +8

13 * 18=210 (We have to always add a zero to the right of the number)

Then we multiply the 3 by the 8, which is 24 and add that to the 210.

So, +3 +8

13 * 18=210

+24

-----

234

Therefore, 13*18=234

You can also apply this rule for all of the other base numbers such as 20, 30, etc. BUT BEWARE, if you use 20 as a base number, for example, you're gonna have multiply the sum of the difference between the number and the base number to the other number by two (and if it was 30 by 3, etc)

Example: +3 +8

23 * 28 = ?

Now we have to add the 3 to the 28, which will be 31 and multiply the 31 by 2 so it'll be 62.

+3 +8

So now you'll use the 62 to start off, 23 * 28 = 620 (never forgetting to add that zero)

And then you multiply the 3 by the 8 just the same and add that to the 620, so: +3 +8

23 * 28 = 620

+24

------

644

Warning: if you're dealing with a number that goes below the base number, such as, for example, 18*26=? You are simply gonna have to apply the signal rules.

So, this would be: -2 +6

18 * 26=? (If we wanted to use 20 as the base, which would be easier in this situation than using ten, for example).

Now, the easiest thing to do here is to subtract 2 from the 26 (which is 24 but we're using base 20 so you need to multiply it by 2, 24*2=48) so it gets like:

-2 +6

18 * 26= 480 (don't forget the zero!)

And now you multiply the (-2) by 6 which is -12 and instead of adding you're gonna subtract 12 from the 480, so: -2 +6

18 * 26= 480

-12

-----

468

(An easy way to do this subtraction mentally is by subtracting 10 from the 480, which is 470 and then subtract the remaining 2 from the 470, which would give 468.

And here we have our result: 18*26=468

Now, onto the last part of this post. If both of your numbers are close to 50, you can totally use 50 as a base, so for example, if you've got:

-3 +3

47 * 53=?

What we'll do here is still subtract 2 from 53 (or add 3 to 47, it's irrelevant which one you choose cause they're both the same number, 47+3=50 and 53-3=50 as well)

Now, an easy way to reach the number multiplied by 5 (or by 50 if you count the zero) is to multiply it by 100 first so: 50*100=5000 and to divide it by 2, so 5000/2=2500.

Now you get: -3 +3

47 * 53= 2500 (the zero is already there cause we multiplied it by 50 instead of 5)

And we simply do, (-3)*3=(-9) and subtract it from 2500 (an easy way to do this mentally is to subtract 10 and add 1), so: -3 +3

47 * 53= 2500

-9

------

2491

This is all for this post, you can find a more in-depth explanation in these videos:

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Feel free to reply to this thread with your questions, and share tips and tricks you personally use to do fast basic maths at the Poker table, or simply at home (it can be on addictions, subtractions, multiplications, divisions, percentages, ratios, anything helpful to Poker really).

Good luck mates!