Internal Concept of Times Table of Eighteen

Now let’s have a look on the table of eighteen.

Here is the table of eighteen as given in textbooks etc.

          18 x 01 = 018

          18 x 02 = 036

          18 x 03 = 054

          18 x 04 = 072

          18 x 05 = 090

          18 x 06 = 108

          18 x 07 = 126

          18 x 08 = 144

          18 x 09 = 162

          18 x 10 = 180

Tip 1: Simply sum up the number twice then subtract the answer from zero padded answer.

18 x 01 = 018 = ((01 x 2) x 10) - (01 x 2) = (02 x 10) - 02 = 020 - 02

18 x 02 = 036 = ((02 x 2) x 10) - (02 x 2) = (04 x 10) - 04 = 040 - 04

18 x 03 = 054 = ((03 x 2) x 10) - (03 x 2) = (06 x 10) - 06 = 060 - 06

18 x 04 = 072 = ((04 x 2) x 10) - (04 x 2) = (08 x 10) - 08 = 080 - 08

18 x 05 = 090 = ((05 x 2) x 10) - (05 x 2) = (10 x 10) - 10 = 100 - 10

18 x 06 = 108 = ((06 x 2) x 10) - (06 x 2) = (12 x 10) - 12 = 120 - 12

18 x 07 = 126 = ((07 x 2) x 10) - (07 x 2) = (14 x 10) - 14 = 140 - 14

18 x 08 = 144 = ((08 x 2) x 10) - (08 x 2) = (16 x 10) - 16 = 160 - 16

18 x 09 = 162 = ((09 x 2) x 10) - (09 x 2) = (18 x 10) - 18 = 180 - 18

18 x 10 = 180 = ((10 x 2) x 10) - (10 x 2) = (20 x 10) - 20 = 200 - 20

Tip 2: Justify the answers with help of sums of digits.

          18 x 01 = 018 = 0 + 1 + 8 = 9

          18 x 02 = 036 = 0 + 3 + 6 = 9

          18 x 03 = 054 = 0 + 5 + 4 = 9

          18 x 04 = 072 = 0 + 7 + 2 = 9

          18 x 05 = 090 = 0 + 9 + 0 = 9

          18 x 06 = 108 = 1 + 0 + 8 = 9

          18 x 07 = 126 = 1 + 2 + 6 = 9

          18 x 08 = 144 = 1 + 4 + 4 = 9

          18 x 09 = 162 = 1 + 6 + 2 = 9

          18 x 10 = 180 = 1 + 8 + 0 = 9