@brin-bellway not reblogging the whole post but
The method of addition described in the OP [adding 7+6 by observing that 7+3=10, 6=3+3, so 7+3+3=10+3= 13] is implicitly being contrasted with some “normal” way, and I’m curious what that normal way actually is. Anyone know?
I don’t know if this is the “normal” way, but I do mental arithmetic by having all the single-digit additions cached (so 7+6=13 is a one-step result of the method), and doing stuff similar to the OP if I am unsure/forgot/dealing with longer numbers I don’t want to do digit-by-digit. Note that OP is implicitly doing some results caching of their own to remember that 7+3=10 and 3+3=6
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I find 3+3=6 much more intuitive and cache-y than 7+6=13, because the first one isn’t overflowing into another digit.
The way you echo back the description of the method, while not wrong really, makes it sound a lot more abstract than it feels in my brain. It feels more like the numbers are made of something with the consistency of dough or soft clay, and I tear a chunk off of one number and stick it onto the other one, then look at the sizes of the resulting two piles of number. Or maybe pouring water from one jug to another until it’s full and then looking at the amount leftover in the first jug, kind of like that puzzle in Die Hard with a Vengeance†. (I always did like that movie as a child, though I would tend to forget that not all of the movie was puzzles and end up unpleasantly surprised by the beginning and end.)
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Quite possibly caching everything is the normal way, yeah. I know it’s the normal way to do 1×1-digit multiplication. The kids in my Girl Scout troop made fun of me for not having the times tables memorised: I never bothered and just worked them out on the fly as needed. Some of them have ended up ingrained through sheer use, but I never did put any deliberate effort into ingraining them.
(ingrained-through-sheer-use rather than through any deliberate effort is also how I learned to touch-type [link])
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†For those of you unfamiliar: you get a 3-gallon jug, a 5-gallon jug, and a fountain (from/to which you may both take and give water). Measure out 4 gallons. (also do it in two minutes or a bomb goes off, because supposedly this is an action movie and not edutainment)
Tags:
#my childhood #math #reply via reblog #is the blue I see the same as the blue you see #death mention #bullying mention
Brinens and Things 