1, approximate value of pi: 3,1415926;

2. Body temperature: 37, 5 degrees;

3. price: 3. 50 yuan;

4. Height: 1, 65 meters;

5. Weight: 8 or 8 kilograms;

6. Vision: 2, 5;

7. Time: Saturn takes about 29 or 5 years to orbit the sun;

8. Score: 97, 5 points;

9. Percentage point: decrease by 0. 1 percentage point;

10, length: 1, 5cm.

Endless decimal

A decimal with a finite number of digits after the decimal part. For example, 3. 1465, 0.364, 8.32 18798456, etc. All finite decimals belong to rational numbers and can be converted into component numbers.

A simplest fraction can be converted into a decimal finite fraction if and only if its denominator contains only prime factors 2 or 5 or both. Similarly, a simplest fraction can be transformed into a finite fraction of the base of a positive integer if and only if the prime factor of its denominator is a subset of the prime factor of the base.

repeating decimal

A number or numbers that start from somewhere in the decimal part and appear repeatedly in turn are called cyclic decimals. Such as1/7 = 0.142857142857,1/6 =1.83333, etc. Cyclic decimals also belong to rational numbers and can be converted into component numbers.

Infinite non-repeating decimal

There are infinitely many numbers in the decimal part, and the decimal with one or several numbers that do not appear repeatedly in turn is called infinite acyclic decimal, such as pi = 3.14159265358979323 ..., and the base of natural logarithm e = 2.71828182823. Infinitely cyclic decimals, that is, irrational numbers, cannot be converted into component forms.