Suppose the number of people in the composition group is x,

Then by the science and technology group: x = 9: 10,

Science and technology team = 910x;

According to composition group: Math group = 5: 7,

Math group =75x,

9 10x+75x=69，

(9+ 14)x=690，

x=30，

75×30-30=25×30= 12 (person);

Answer: There are more people in the math group than in the composition group 12.