Is 39 squared equaled 1521

Answer 1

39 squared -or- 392 = 1521

Yes it is 1521. How?

Can you calculate a number between 30 - 70 being squared in 5 secs?

Here's the trick:

39 is 11 less than 50 so take away 11 from 25 which is 14.

14 is automatically your first two digits.

Then the number you have taken away which in this case is 11, you square that number

11x11= 121.

Now this is a 3 digit number so you would and the 1 to the 4 to make 5.

put all the digits together which will make 1521.

Now say for instance how to do it with a number over 50. Lets try 62 (number between 50-70)

Here's the trick:

62 is 12 more than 50. Plus 12 to 25 which is 37. this is now automatically your first two digits.

Then the number you have added which is this case is 12, you square it which is 144.

Now this is a 3 digit number so you would add the 1 to the 7 which is 8.

put all the digits together to make 3844.