What is the easiest way to subtract 75?
Let me ask another question.
What is the easiest way to take 9 from 63 in your head?
63 – 9 =
I am sure you got the right answer, but how did you get it?
Some would take 3 from 63 to get 60, then take another 6 to make up the 9 they have to take away, and get 54.
Some would take away 10 from 63 and get 53. Then they would add 1 back because they took away 1 too many. This would also give 54.
Some would do the problem the same way they would when using pencil and paper. Th is way they have to carry and borrow in their heads. Th is is probably the most diffi cult way to solve the problem.
Most people find the easiest way to subtract 9 is to take away 10, then add 1 to the answer. The easiest way to subtract 8 is to take away 10, then add 2 to the answer. The easiest way to subtract 7 is to take away 10, then add 3 to the answer.
What is the easiest way to take 90 from a number?
Take 100 and give back 10.
What is the easiest way to take 80 from a number?
Take 100 and give back 20.
What is the easiest way to take 70 from a number?
Take 100 and give back 30.
If we go back to the problem we were working on, how do we take 75 from 12,200?
We can take away 100 and give back 25.
Is this easy? Let’s try it. Twelve thousand, two hundred minus 100?
Twelve thousand, one hundred. Plus 25? Twelve thousand, one hundred and twenty-five. Easy.
Let me ask another question.
What is the easiest way to take 9 from 63 in your head?
63 – 9 =
I am sure you got the right answer, but how did you get it?
Some would take 3 from 63 to get 60, then take another 6 to make up the 9 they have to take away, and get 54.
Some would take away 10 from 63 and get 53. Then they would add 1 back because they took away 1 too many. This would also give 54.
Some would do the problem the same way they would when using pencil and paper. Th is way they have to carry and borrow in their heads. Th is is probably the most diffi cult way to solve the problem.
Most people find the easiest way to subtract 9 is to take away 10, then add 1 to the answer. The easiest way to subtract 8 is to take away 10, then add 2 to the answer. The easiest way to subtract 7 is to take away 10, then add 3 to the answer.
What is the easiest way to take 90 from a number?
Take 100 and give back 10.
What is the easiest way to take 80 from a number?
Take 100 and give back 20.
What is the easiest way to take 70 from a number?
Take 100 and give back 30.
If we go back to the problem we were working on, how do we take 75 from 12,200?
We can take away 100 and give back 25.
Is this easy? Let’s try it. Twelve thousand, two hundred minus 100?
Twelve thousand, one hundred. Plus 25? Twelve thousand, one hundred and twenty-five. Easy.
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