Short cut trick to find square of a number ending with 5 and 05

Short cut trick to find square of a number ending with 5 and 05

 

Short cut trick to find square of a number ending with 5

Step I: Multiply the first digit by the first digit plus 1

Step II: Write 25 next to result of Step I.

 

Eg: 25² = 2 x (2 + 1)     25  = 625

Eg: 45² = 4 x (4 + 1)     25  = 2025

Eg: 75² = 7 x (7 + 1)     25  = 625       

 

Short cut to find square of a number ending with 05

Step I: Square the preceeding number to 05 and multiply by 10 and add the same number.

Step II: Write 025 next to result of Step I.

Eg: 305² =  3² x 10 + 3      025  = 93   025 = 93025

Eg: 905² =  9² x 10 + 9      025  = 819   025 = 819025

Eg: 705² =  7² x 10 + 7      025  = 497   025 = 497025

Eg: 605² =  6² x 10 + 6      025  = 363   025 = 363025