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We don't have to rely on the standard algorithm when subtracting. Here are other ways to subtract.
20,344 views • 2 years ago •via X (Twitter)
10 Comments

@rye723 @HurdleLatoya @luvmesumath @WandaCalhoun13

the way i mentally do it is first do 80-30=50, then add 3 more.

added 1 to each number (76-40) = 36

Love the last one. 7 [effectively 70] minus 3 [effectively 30] = 40 then 5 minus 9 = -4 then 40-4 = 36.

2nd graders not relying on standard algorithm…. They are huge fans. #mathmotivation

Awesome! Have they practiced negative number results for subtraction before this?

I like the last one, subtracting from left to right. But is it applicable to 3 digits or above?

I think as: 80 is 50 away from 30. Then another 2 away for 28 (52 total so far) and another 1 away for 81 (53 total).

Pocket change use to be counted upwards when the sales clerk was giving change.

That last approach is interesting. Thanks.



