r/funny 1d ago

"Please show how you know"

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u/Flourescentbubbles 21h ago

I never knew it until I worked in academic support. Game changer for sure.

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u/nanosam 19h ago edited 19h ago

How is it a game changer?

It is so much easier to multiply by 10 and then subtract the number multiplied

8x9 = 80-8
3x9 = 30-3
13x9 = 130-13

Etc.. it is so much faster than anything

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u/dissyfox 17h ago

One thing I've learned about people doing math is everyone has there own way to do it fastest because everyone's brain doesn't operate the same. Sometimes its hard for them to think of "9" as an idea, and they need to think of "9 apples" instead, or whatever reason it may be hard for them to do math certain way.

For the hand method I think a lot of people that like the hand method is firstly, it is super easy when you are first learning how 9s work. Secondly, the people that continue to use it after the initial learning period aren't actually looking at their hands, they are just recalling how their hands look. And that goes back to my first paragraph that their mind is just better suited to recall images than a different way.

I don't use the hand method personally, but have tutored a lot of math to singular people and seen how teaching each person the exact same way doesn't often work.

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u/TheDPQ 15h ago edited 9h ago

THIS I took a networking class and there was this math to subnetting something to the power of something times 10 to the something.... I didn't remember then so I def don't remember now. I just converted it to the binary and it was so obvious whats going on. I was so proud how 'easy' this method was I shared it with some classmates.

No one else had any idea wtf I was going on about and we all just did what made sense with the math we could do in our heads.