=288- 198,

=90 (minutes);

Answer: The score of the final exam of the fourth grade mathematics is 90 points.

The bar chart is as follows:

(2)( 100-90)÷90,

= 10÷90,

≈ 1 1. 1%.

Answer: The grade of the final exam in the fifth grade is about 1 1. 1% higher than that in the fourth grade.