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So on paper: you write down 8 right away, and add an underline each time the next column results in a carry. When doing mental math on-the-fly: the carries may
by Leftium 2y ago
So on paper: you write down 8 right away, and add an underline each time the next column results in a carry.
When doing mental math on-the-fly: the carries may chain all the way back to the least significant digit, but most of the time you only need to look ahead one or two columns.
- rahimnathwani 2y agoI love it!
- Leftium 2y agoThe trick to left-to-right subtraction is to write down the resulting difference right away, then "slash" through it to borrow from it. When I was designing my custom flashcard program, I played with around with different input methods because that became the bottleneck: You can actually spit out the answer faster than someone can enter the digits into a calculator! (as someone else reads off the problem)