The average person's IQ is between 9-11, and those above 11 have relatively high IQ, while those below 9 have relatively low IQ. IQ is a quantitative index that indicates the level of human intelligence. It was put forward by German psychologist Steen in 1912. IQ is the abbreviation of intelligence quotient, and IQ is expressed in English. IQ is the quotient obtained by dividing the intellectual age by the physiological age. The calculation formula of IQ is as follows: IQ = Ma÷÷÷÷÷÷é1, and IQ indicates people's intelligence. The higher the IQ, the smarter it means. Physiological age refers to the actual age of a child after birth. Intellectual age or psychological age is the age measured according to intelligence measurement. Intellectual age can only indicate the absolute level of intelligence, but not the level of intelligence of children of different physiological ages. For example, A child is 5 years old physically and 6 years old intellectually, while B child is 1 years old and 11 years old intellectually. Both children are one year older than their physical age, so it is difficult to compare their intelligence. Using IQ can compare their intelligence level relatively. The IQ of A children is 5/6×1=12, and that of B children is 11/1×1=11. From the IQ of children in A and B, we can think that the intelligence level of children in A is higher than that of children in B..