1, because the average score of three subjects is 75, the average score ×3 can get the total score of three subjects, and because the ratio of three subjects is 8: 9: 8; Then the total score is 8+9+8=2 copies. Divide the total score by the total number of copies to get the score of each copy, and then multiply it by the number of copies in the math class.

2. Solution: 75×3÷(8+9+8)=225÷25=9 (points), mathematics: 9×9=8 1 (points), and its mathematical score is 8 1.

3. Total score: 88 * 3 = 264; 7+8+9=24, language: 264*7/24 = 77, mathematics: 264 *[8/(7+8+9)] =88, English: 264 *[9/(7+8+9)] =99.

4. The purpose of division is to find the quotient, but when you suddenly can't see how many quotients are contained in the dividend, you can use the method of trial quotient and quotient estimation to see how many divisors are contained in the highest digit of the multiplicand (that is, how many times the quotient is contained), and then add several complements from the standard number to get the quotient.

5. Small array: When the dividend contains divisor 1, 2 and 3 times, the periodic method is: dividend contains quotient 1 time; complement is added from standard 1 time; dividend contains quotient twice; complement is added from standard twice; dividend contains quotient three times; complement is added from standard three times.

Xiao Ming's average score in Chinese, mathematics and science in the final exam is 85. After his English grades were announced, his average score increased by 2 points. What's your English score?

85x3 = 255, (85+2) x4 = 348, 348-255 = 93, with an English score of 93.

Xiao Ming's average score in Chinese and mathematics in the final exam is 92. After his English grades were announced, his average score increased by 2 points. What's his English score?

94*3-92*2=98 points.

Xiaoming got an average of 90 points in Chinese and English in the final exam. After the math scores were announced, his average score increased by 3 points. What's his math score?

93*3=279 (total score of English and Chinese), 90*2= 180 (total score of English and Chinese), 279- 180=99 (three grades minus English and Chinese, mathematics).