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It wasn't until I learned about for-loops that I started thinking of multiplication as repeated addition and division as repeated subtraction. Before then I tho

by _bxg1 7y ago

It wasn't until I learned about for-loops that I started thinking of multiplication as repeated addition and division as repeated subtraction. Before then I thought purely in terms of geometry.

novok 7y ago
I think it depends on how you were taught the concepts in elementary school. I think a lot of it is based on things like bar charts[0] and visual representations at first, so it's possible you were never taught how it was repeated subtraction and addition, how powers are repeated multiplication and so on. https://en.wikipedia.org/wiki/Singapore_math#Bar_modeling https://en.wikipedia.org/wiki/Singapore_math#Bar_modeling
- _bxg1 7y ago
  Yep. I remember in college when I made that connection and realized you could create infinite "levels" of operation, with each repeating the previous one N times.
  - pas 7y ago
    https://www.youtube.com/playlist?list=PL3A50BB9C34AB36B3 https://www.youtube.com/playlist?list=PL3A50BB9C34AB36B3 For anyone interested in going down the rabbit hole of those infinite levels.
  - rocqua 7y ago
    If you do this, 2 and 2 will always make 4, no matter what level you go to.
  - pbhjpbhj 7y ago
    Up-arrow notation ftw.
    - all2 7y ago
      I'm missing the context here. The only arrows I'm familiar with are vector notation and ion spin notation.
      - applecrazy 7y ago
        I think they're talking about this, which appeared in a front-page HN post from yesterday: https://en.wikipedia.org/wiki/Knuth%27s_up-arrow_notation https://en.wikipedia.org/wiki/Knuth%27s_up-arrow_notation
        pbhjpbhj 7y ago
        Not that story in particular, it's a perennial story on HN - I first learnt about that notation through the "largest number you can write on a postit note" challenge.
- geomark 7y ago
  At my kid's school they start teaching division as "sharing" - a kid has 10 pieces of candy he wants to share with 5 friends; how many pieces can he share with each friend. Later they describe it as repeated subtraction - how many times can his 5 friends take a piece of candy from the pile of 10 pieces.

by _bxg1 7y ago

It wasn't until I learned about for-loops that I started thinking of multiplication as repeated addition and division as repeated subtraction. Before then I thought purely in terms of geometry.

novok 7y ago

I think it depends on how you were taught the concepts in elementary school. I think a lot of it is based on things like bar charts[0] and visual representations at first, so it's possible you were never taught how it was repeated subtraction and addition, how powers are repeated multiplication and so on. https://en.wikipedia.org/wiki/Singapore_math#Bar_modeling https://en.wikipedia.org/wiki/Singapore_math#Bar_modeling

_bxg1 7y ago
Yep. I remember in college when I made that connection and realized you could create infinite "levels" of operation, with each repeating the previous one N times.
- pas 7y ago
  https://www.youtube.com/playlist?list=PL3A50BB9C34AB36B3 https://www.youtube.com/playlist?list=PL3A50BB9C34AB36B3 For anyone interested in going down the rabbit hole of those infinite levels.
- rocqua 7y ago
  If you do this, 2 and 2 will always make 4, no matter what level you go to.
- pbhjpbhj 7y ago
  Up-arrow notation ftw.
  - all2 7y ago
    I'm missing the context here. The only arrows I'm familiar with are vector notation and ion spin notation.
    - applecrazy 7y ago
      I think they're talking about this, which appeared in a front-page HN post from yesterday: https://en.wikipedia.org/wiki/Knuth%27s_up-arrow_notation https://en.wikipedia.org/wiki/Knuth%27s_up-arrow_notation
      - pbhjpbhj 7y ago
        Not that story in particular, it's a perennial story on HN - I first learnt about that notation through the "largest number you can write on a postit note" challenge.
geomark 7y ago
At my kid's school they start teaching division as "sharing" - a kid has 10 pieces of candy he wants to share with 5 friends; how many pieces can he share with each friend. Later they describe it as repeated subtraction - how many times can his 5 friends take a piece of candy from the pile of 10 pieces.