If u had a child, how would u describe the definition of a rational number?

Answer 1

If the kid's too young, I wouldn't try to explain it, but if they're old enough to understand, I'd go with something to the effect of "it's a number that goes on forever. You could keep going and going, but you'd never get to the end of it, and you'd never find a repeating pattern in it. Like Pi: 3.14159265... it goes on and you can't get to the end, because there is no end."

Answer 2

A rational number is any number that can be expressed in the form a/b where a and b are integers and b is not zero.

I would teach a child that a rational number is any number that can be expressed in *finite form* in some radix system. Example 1/2 = 0.5
1/3 = 0.1 (base 3) so it's rational. An irrational number is one that cannot be expressed finitely in any radix system but has a recognizable pattern. Finally I would call any number that is not rational or irrational a transcendental number. Example pi, e, sqrt(2).

This is not what universities teach but then again, look at the disasters produced by such institutions. Do you want your child to be a fine young moron like most of the math professors?

Answer 3

Forget about mathematics, use English, or human terms. A rational number is a number that has rational. A search on google gives this: "consistent with or based on or using reason" [1]. In other words, there is a pattern, a trend. In contrast, an irrational number is one that has no pattern or trend, sort of unpredictable.

E.g. rational numbers: 2 as a single digit '2'. 1/3 as a 0 follows by a decimal point and endless repetitions of digit '3', 1/11 as a '0.' follows by endless repetitions of 2-digit '09', any finite sequence of digits, because being finite is the rationale.

An irrational number can be formed by writing down an infinite sequence of digits without using any reason. Thus, even the person writing it cannot predict the next digit until he/she decided what to write down next.

ps: So, is sqrt(2) truly irrational in human terms, or just pseudo irrational, just like there might be no true random numbers, but just pseudo random numbers?

Answer 4

A rational number is one that can be expressed as a ratio (a fraction). Some number can not be. Pi for example is irrational and can not be expressed by a fraction. The closest fraction to pi is 22/7. You can find a value for pi (=pi() in excel). You can then let them play with a calculator to see how close they can get with a ratio.

You can also experiment with rational and non-rational numbers.

Answer 5

I would describe the definition as a sentence explaining what a rational number is.

Answer 6

Every number can be written as a decimal number (if the number is written as a fraction-divide in the calculator, although any fraction is a rational number). A rational number will either terminate (ex 2.34 or 2.777774) or will repeate in a pattern (ex 2.777777.... or 2.34134341341....). An irrational number will not terminate or repeate a pattern.


Note: some rational numbers do "go on forever", 1/3 = .3333..... which goes on forever.

Answer 7

For a child, start with cutting things into even pieces.
1/8 is what you get when tear a piece of paper into 8 equal pieces.

3/8 is what you get when you collect 3 of those 8 pieces together.

You might also explain how it works with the fraction of an inch markings on a ruler.

Answer 8

Forget the math and take English.