Strictly according to the meaning of the question, people who take part in one subject, two subjects and three subjects are incompatible with each other, that is to say, those who take part in one subject do not belong to two subjects, those who take part in two subjects do not belong to one subject, and so on.

So the answer is simple: 203+179+165+143+16+97+89 = 992 (person).

Make the topic a little more difficult for the Olympics, and the topic should be revised as follows? ：

A primary school held a math, Chinese and common sense contest, with 203 participants, Chinese contest 179 participants, common sense contest 165 participants, math and Chinese contest 143 participants, and math and common sense contest16 participants.

Solution: As shown in the figure.

d=89

e= 143-89=54

f= 1 16-89=27

h=97-89=8

a=203-89-54-24=33

b= 179-89-54-8=28

c= 165-89-8-27=4 1

A+B+C+D+E+F+H = 33+28+41+89+54+27+8 = 280 (person)