problem 1
we want 15% of 80 bucks
first we find 10% which is super ez just drop the zero from 80 and it becomes 8
then we need the missing 5%
since 5 is half of 10 the value of 5% is gonna be half of 8 which is 4
then just add 8 and 4 and u get 12 bucks off
if we wanted the final price just do 80 minus 12 which gives 68 bucks (´｡• ᵕ •｡`)
problem 2
we want 45% of 200 students
the trick here is finding 50% first bc 50% is exactly half of everything
half of 200 is 100
but we want 45% so we went over by 5% right
lets find how much 5% is now
10% of 200 is 20 so half of that which is 5% is gonna be 10
now just take the 100 that was 50% and subtract the 10 that is 5%
100 minus 10 gives 90 students playing (￣▽￣)
problem 3
we want 25% of 120 coins
25% is the same as dividing by 4 or doing half of half
first we do half of 120 which gives 60
then we do half of 60 which gives 30
done u spent 30 coins (o･ω･o)
and when the number is yabai?
some numbers are too yabai and it becomes full meme trying to do it mentally
like if the exam asks 17% of 438... then u cant force it in ur head or we get totally lost in the numbers and mess everything up (×_×)
thats why when the number is ugly and yabai like this we just do it on paper. the most sigma hack to do on paper without drawing the whole rule of three is just multiply normally and forget the percentage at first
u just do 438 times 17 on the corner of the page and it gives 7446
since its percentage u just move the decimal two places to the left and plim it becomes 74.46 (ﾉ◕ヮ◕)ﾉ*
way safer than trying to hold so many numbers in ur mind and ending up tilted in the middle of the exam ( ˘▽˘)っ
pretty easy right now ur ready to calculate anything in ur head without suffering