Multiplication of 9 with any number
Multiply the number by 10 and then subtract the number from it to get answer
1. 18 x 9 = 18 x (10-1)
= 18 x 10-18 = 180-18 = 162.
2. 187 x 9 = 187 x (10-1) = 1870-187 = 1683.
3. 1864 x 9 = 1864 x (10-1)
= 18640-1864 = 16776