Squaring Any Two-Digit Number Ending in 5
Squaring a two-digit number ending in 5 is a special case of the short cut multiplying any two-digit numbers ending in 5. In this particular case, the tens digits are equal.
Rule;multiply one more than the tens digit by the original tens digit and affix 25 to the result.
For example, we shall square 45. First, add 1 to the tens digit
4 + 1 = 5
Next, multiply by the original tens digit.
4 x 5 = 20
To this affix 25.
2,025
And we have the answer.
45 x 45 =2,025
Remember to merely attach the 25 to the product: do not add it to the product.
From this rule we see that the square of any two-digit number ending in 5 always has 5 as its units digit and 2 as its tens digit.
Squaring any number ending in 5
Rule: multiply the complete number to the left of the 5 by one more than ttself and affix 25 to the result.
To demonstrate, we shall find the square of 195. To demonstrate, we shall find the square of 195. The complete number to the left of the 5 is 19. Rising this one number higher gives us 20.
20 x 19 = 380
To whiich 25 is affixed.
38,025 answer
