MemoryMentor’s Blog

Finding the square of a number made up of threes

Choose a number made up of threes.

1. Add 1 n-1 times (where n is the number of 3’s)
2. Add a zero
3. Add 8 n-1 times (where n is the number of 3’s)
4. Add a nine

E.g. Find the square of 333

1. Since we need to find the square of 333(which has three 3’s, n=3)
2. Add 1 n-1 times (3-1 =2) 11
3. Add a zero 110
4. Add 8 n-1 times (2 times) 11088
5. Add a nine 110889

Find the square of 3333333
1. n=7 ( as the number has 7 3’s)
2. Add 1 n-1 times (7-1 =6) 111111
3. Add a zero 1111110
4. Add 8 n-1 times (6 times) 1111110888888
5. Add a nine 11111108888889