Solution: 0.9x=9.9

x= 1 1

(2) From 29.6, subtract 2.4 and then add 0.8 (always subtract 2.4+0.8). Do (37) operations in this order, and the number of operations is equal to 0?

(3) The library bought 80 story books and 65 science and technology books. The total price of story books is 403.5 yuan more than that of science and technology books, and each science and technology book is 12.5 yuan. How much is each story book? 80x-65* 12.5=403.5 solution: x= 15.2 yuan.

(4) Party A and Party B * * * process 500 parts. It is known that Party A processes 70 more parts than Party B. How many parts do they each process? (Indicate Party A and Party B)

Let A be X, x+(x-70)=500, and the solution is: x=285, and B is 2 15.

(5) Mom and Dad go shopping. Mother gave her father half of the money she brought, and she used the rest to buy 2 Jin of fish. Dad used his money to buy some apples, and each kilogram of fish 18 yuan is more expensive than one kilogram of apples 10 yuan. How many kilograms of apples did dad buy? How much did mom bring?

Suppose mom brought x yuan. 18*2=x/2 x=72 yuan 72/2 = (18-10) * y y = 4.5kg.

(6) Basketball is 90 yuan and volleyball is 70 yuan. The PE teacher bought these two kinds of balls with 900 yuan. Can I buy at most (12) two kinds of balls?

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