The Relocation Property (Subtraction)
As seen from working with the Relocation Property using just the addition operator, we can solve problems a whole lot easier when we employ it. But what about subtraction? Hmm not so cut and dry anymore...
Consider the expression
We cannot rearrange solely the numbers for easier calculation, because we have addition and subtraction. Here is where the Relocation Property comes to the rescue. We will consider each operation sign to be "glued" (as part of the act in the story) with the number that follows it.
The Relocation Property states:
When writing your solution try to be as thorough and true to the thinking of yourself as a grade five student, who is trying their utmost to get out of developing their mathematical selves from the problem.
The answer is 80.
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1 solution
Moderator note:
Alternatively, we can split the terms up into the tens digit and the ones digit, which make it easier to see the pairing into "multiples of ten".
Now it is easy to rearrange the numbers in our example. We have a 19, a plus 26, a minus 3, a minus 9, a plus 4, and a plus 43. Rearranging to end up with as many multiples of ten as possible gives us 1 9 − 9 , added to 2 6 + 4 , added to 4 3 − 3 :
1 9 + 2 6 − 3 − 9 + 4 + 4 3 = 1 9 − 9 + 2 6 + 4 + 4 3 − 3 = 1 0 + 3 0 + 4 0 = 8 0