Multiplication table

In mathematics, a multiplication table (sometimes, less formally, a times table) is a mathematical table used to define a multiplication operation for an algebraic system.

The decimal multiplication table was traditionally taught as an essential part of elementary arithmetic around the world, as it lays the foundation for arithmetic operations with base-ten numbers. Many educators believe it is necessary to memorize the table up to 9 × 9.

The oldest known multiplication tables were used by the Babylonians about 4000 years ago. However, they used a base of 60. The oldest known tables using a base of 10 are the Chinese decimal multiplication table on bamboo strips dating to about 305 BC, during China’s Warring States period. “Table of Pythagoras” on Napier’s bones.
— Wikipedia

×0123456789101112
00000000000000
10123456789101112
2024681012141618202224
30369121518212427303336
404812162024283236404448
5051015202530354045505560
6061218243036424854606672
7071421283542495663707784
8081624324048566472808896
90918273645546372819099108
100102030405060708090100110120
110112233445566778899110121132
1201224364860728496108120132144

Basically multiplication table is set of multiply operations between two numbers. And there no difference which number is first or second, because it’s following Commutative Associative and Distributive Laws property.

Half of the table is a mirror image of the other (diagonal line from top left to bottom right), and you can memorize first part (small number x big number).

You can find that some operations are repeated in the multiplication table and that operations are the patterns.

Better to learn mutliplication table in chunks:

  • Columns: 1-5, Rows: 1-5
  • Columns: 6-9, Rows: 1-5
  • Columns: 1-5, Rows: 6-9. It’s mostly same as previous, but learn/practice it too.
  • Columns: 6-9, Rows: 6-9

Patterns

Multiples of even numbers or even and odd numbers are always even numbers. 2x, 4x, 6x, 8x, 10x, 5x6, 9x8, etc.

2× is just doubling the number, 2x2=4, 2x3=6, 2x4=8, 5x2=10, 6x2=12, etc.

5× has a pattern: 5, 10, 15, 20, etc. It ends in either 0 or 5.

9× has a pattern, too: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90. Now, notice how the “ones” place goes down: 9, 8, 7, 6, …? And at the same time, the “tens” place goes up: 1, 2, 3,…? Well, your hands can help! Example: to multiply 9 by 8: hold your 8th finger down, and you can count “7” and “2” … the answer is 72.

10× is maybe the easiest of them all … just put a zero after it.

11× is mostly easy: from 11×2 to 11×9 you just put the two digits together. 11×2=22, 11×3=33, …, 11×9=99 and 11×11=121, 11×12=132

2x12 → double 2x12 → 24 3×12=36 4×12=48 5x12 → ends in 0, 60 (pattern above) 6×12=72 7×12=84 8×12=96 9×12=108 10x12 → add 0, 120

TODO: more patterns Multiplication Tips and Tricks

Training