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Science,English,and math Ⅱ

No.33　17/04/30 10:20
燻し銀三 ( 50代 ♂ Oe38xe ) あ+あ-

【The part of a minus number】

《If making use of a number dynamically,a minus number appears inevitably》

In other words,there are lots of phenomena naturally which correspond to the minus number. The author indicates some examples for it.

For example,let's suppose that I had income of $ 300,and if spending $ 500, I'm $ 200 in the red. Then a theory that the part of the red is minus stands up.

Or there is a basic point. Let's suppose that its eastward was plus. Then if walking 7kilometers eastward and walking 10 kilometers westward,it means 7 - 10 = -3. It means I'm at the point of 3 kilometer the westward and I'm at the point of -3 kilometers the eastward. It's the way of thinking as vector.

Descartes displayed some numbers on a number line 数直線. The numbers displayed on the number line would have extended to a real number later. The number line on which an equation of 3-5 is displayed is in the book.

The real number means that a rational number like a fractional number or…