Which equals 29^2 x .01
=> ((28 x 30) +1) X .01
=> (840 + 1) x .01
=> 8.41
28 x 30 is an easy mental calculation, as is adding 1, as is moving the decimal place over 2 places. I am teaching this to 4th graders, in two weeks. % to decimal is next week. They can square 2-digit numbers in their heads, already.
,25/,5 x 100/100 = 25/50 = 1/2
Why was that hard?
100/100 = 1, because any number divided by itself is 1.
And any number multiplied by 1 is still that number.
TBH, I moved the decimal over 2 places on the numerator and denominator and simplified 25/50 to 1/2 because It is easier to do in my head. Some of the other paths are too complicated when I am going to sleep.