GMAT数学辅导：算术知识点全解析(小数和实数)

　　GMAT数学辅导：算术知识点全解析

　　三.小数：decimals

　　科学计数法：scientific notation

　　Sometimes decimals are expressed as the product of a number with only one digit to the left of the decimal point and a power of 10. This is called scientific notation. For example, 231 can be written as 2.31102 and 0.0231 can be written as 2.3110-2. When a number is expressed in scientific notation, the exponent of the

　　10 indicates the number of places that the decimal point is to be moved in the number that is to be multiplied by a power of 10 in order to obtain the product. The decimal point is moved to the right if the exponent is positive and to the left if the exponent is negative. For example, 20.13103 is equal to 20,130 and 1.9110-4 is equal to 0.000191.

　　四舍五入：to the nearest

　　小数点：decimal point琾eriod

　　四.实数：real numbers

　　正数和负数：positive and negative numbers

　　绝对值：absolute value