15* 15=225 25*25=625 35*35= 1225 45*45=2025 55*55=3025

65 * 65 = 4225 Can you see the pattern? Followed by 25. The first formula is 1 * 2 = 2, the second is 2 * 3 = 6, the third is 3 * 4 = 12, the fourth is 4 * 5 = 20, the fifth is 5 * 6 = 30, and the sixth is. 85 = 7225. Another example is105 *105 =102510 *1=1/kloc.

24* 15=24*( 10+5)=24* 10+24*5=240+ 120=360

38*9=38*( 10- 1)=38* 10-38* 1=380-38=342

The simple operation of primary school mathematics is nothing more than the use of multiplication and division, sometimes, and sometimes the other way around.