If you need to square a number that ends in 5, there's a quick shortcut to do that.
To calculate the square of 35, for example, just figure out 3 times 3+1, which is 3*4 or 12. Write that in front of 25. The answer is 1225.
It still works with larger numbers: to figure 105 squared, 10 * 11 is 110, so the answer is 11025.
No comments:
Post a Comment