3 * 2/(20- 18)*(20+ 18)= 1 14km

2.

(90+82+86)/2/3=43

(90+82-86)/2=43

3.

96+2 = 98 Xiao Ting

96-2 = 94 small fruits

4.

(39+6)/5 = 9 Xiaoming

9 * 4 = 36 Xiao Wang

Satisfied, please adopt.