Quick maths for the table

You get a few seconds to decide. Nobody works out exact percentages in that time. Good players remember a handful of answers and round everything else. There are eight sums worth being fast at, and each one has a shortcut.

Every drill shows how long your answer took. Right first, then fast: aim for under five seconds on each.

1. Add up the pot

Every price starts with one number: how big the pot will be after you call. It is the pot, plus their bet, plus your call.

Shortcut: keep a running total as the chips go in, so the number is already in your head when the bet comes. At your stakes round to the nearest dollar. Two related sums come up constantly: a fraction of the pot when you bet (a third of $9 is $3), and dollars to big blinds (double it: $15 is 30 big blinds).

2. Shrink the fraction, then read off the percent

The price of a call is your call divided by that final pot. Say you must call $6 and the pot will be $36. Don't divide 6 by 36. Shrink it: both numbers divide by 6, so it is 1 ÷ 6, and a sixth is 17%.

That only works if you know the small fractions cold. These nine are the whole list.

When it won't shrink neatly, round to something that will. $7 into $31 is close to 7 ÷ 28, which is a quarter, so a little under 25%. Or find 10% of the pot ($3.10) and count how many of those your call is: a bit over two, so about 23%. Within a couple of points is all you need.

Two or three of something: 2 ÷ 7 is two sevenths, so 14% twice, 29%. 3 ÷ 8 is three eighths, 12.5% three times, 37.5%.

3. Know the price of each bet size by heart

Most bets are a simple fraction of the pot, and the price of calling each one never changes. Learn six numbers and you can skip sums 1 and 2 most of the time.

How to rebuild it if you forget: pretend the pot is the bottom number of the fraction. A half-pot bet: pot 2, they bet 1, you call 1, final pot 4. Your share is 1 in 4, 25%. Two-thirds: pot 3, bet 2, call 2, final pot 7. Two sevenths, 29%.

The last column is the same idea for your own bluffs: your bet ÷ (your bet + the pot). Half pot risks 1 to win 2, so 1 in 3.

4. Turn outs into a percent

From lesson 2. Count the cards that make your hand, then multiply.

The three to know without counting: a flush draw is 9 outs (about 18% next card), an open-ended straight draw is 8 (about 16%), a gutshot is 4 (about 8%).

5. Compare the two numbers

This is the decision itself. Sum 3 gives the price. Sum 4 gives your chance. If your chance is bigger than the price, call. If not, fold. You never need either number exactly, only which is bigger.

Shortcut: turn the price into outs instead. Half the price is the number of outs you need with one card to come. A half-pot bet needs 25%, so about 12 or 13 outs. A third-pot bet needs 20%, so 10 outs. A quarter-pot bet needs 17%, so 8 or 9. Then just count your outs.

6. Swap between odds and percentages

Players often say "3-to-1" instead of "25%". It is the same thing said another way: three misses for every hit. To get the percentage, add the two numbers and put one over the total.

It works for the pot too. If you must call $5 to win $15, the pot is offering 3-to-1, so you need to win 1 time in 4. Some people find this quicker than sum 2, because you compare "the pot offers 3-to-1" straight against "my draw is 4-to-1 against" and fold.

7. Price your own bet

Before a bluff, you need to know how often it has to work. Before a bet for value, you need to know what you are offering them. Both come from the table in sum 3. This drill uses dollar amounts, so it is sums 1, 2 and 3 together.

8. Stack sums

Three quick checks before you put money in with a speculative hand or a single pair. They are all one division.

• Big blinds: double the dollars. $22 is 44 big blinds.
• Set-mining: the smaller stack should be 15 to 20 times the call. For a $2 call that is $30 to $40.
• Stack-to-pot ratio: the smaller stack ÷ the pot on the flop. Around 3 or less, top pair plays for everything. At 8 or more, it doesn't.

How to drill it

• Learn the two tables first. The nine fractions in sum 2 and the six bet sizes in sum 3. Until those are instant, everything else is slow.
• Ten minutes, most days. Short and often beats one long session. A maths-only session of 20 questions is about right.
• Get it right, then get it fast. Watch the seconds under each answer. Under five is quick enough to use at the table.
• Practise on real pots. When you have folded, price the bet anyway: add up the pot, name the bet size, say the percentage to yourself. It costs nothing and it is the same skill.