What is Black Friday Math? It's the mental math that many individuals will likely be doing as they quickly calculate the 40% or 25% off of the ticketed price. The strategies to compute saving are varied and of those individuals I asked, they all used a different strategy! For instance, let's say you get 75% off an $80.00 item. Here is how some individuals do their mental math:

I know that 50% of 80 is 40. 25% is half of 50%. Since 50% was 40, then 25% must be half of that or 20. Then I added 40 and 20 and I got 60.

I know that 10% of 80 is 8. In order to get 70%, I multiplied 8x7 and got 56. I still need 5% more. I thought 5% is half of 10%, so 5% must be 4. By adding 56 and 4, I got 60.

I know that 75% is the same as ¾. I divided 80 into fourths. Each fourth is 20. Three of them make 60.

I changed 75% to 0.75 and multiplied. 0.75 x 80 is 60.

I know how to find 1%. Move the decimal 2 places to the left. 1% of $80.00 is 0.8 75% is 75 x 0.8 which is 60

I know that if I get 75% off $80.00 $80.00 = 100% I must pay 100% less 75% which is 25% Therefore ¼ of 80 = 20.00 and $80.00  $20= $60.00
Happy Black Friday Shopping!
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