[Harmless Teddy Bear]

Be that as it may my point stands. Kids need to be taught simply not with gobbledygook.

Like this.

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You add six and seven to get thirteen. Write down the three in the ones spot and carry the 10 to the tens spot. Add two and one to make three and the one from the ones spot to make four. Your answer is forty-three.

[jpsb]

"You add six and seven to get thirteen."

Tried and true, always works, every damn time (with positive numbers).

[a fool in paradise]

Agree, add up the columns (displaying the numbers horizontally makes for easy typing by not “cyphering”) from smallest figure (rightmost) and carrying the 1’s (10’s etc.) is still the tried and true method.

I also do darkroom photography and mix chemicals. They are recommended to be at certain temperatures (and the equalize the temperatures between the chemistry so that there isn’t a wide difference than may “shock” the film transparency or emulsion on paper).

Warmer or cooler developer temperatures can also affect the time for development to occur (leading to over/under developed film).

After adhering to the “recommendations” for a period of time, you can stray from the norms with the UNDERSTANDING of what the outcome will be. But it shouldn’t be the starting point.

Measure twice. Cut once. Always good practice.