1, (1) What percentage of the total number of winners in the sixth grade? 1-one fifth-one quarter = 55% (2) If there are 25 winners in the fifth grade, how many are in the sixth grade? 25× (4- 1) = 75 (person) 2. A newspaper, if subscribed once a month, each copy 10 yuan; If you order once a year, you can get a discount of 10%. Subscribe to this newspaper. How much more does it cost to subscribe every year than to subscribe in January? 10×12-10×12× 90% =12 (yuan) 3. Xiaohong's mother bought 2000 yuan of national debt with a fixed term of three years and an annual interest rate of 5.74%. According to the regulations, debt interest does not need to pay taxes. How much principal and interest can she get when it expires? 2000× 5.74 %× 3 = 344.4 (yuan)

4 school B.

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1, 8÷4=2 (cm) perimeter: 2×3. 14=6.28 (cm) area: 2 ÷ 2 = 1 (cm)1×/kloc-0. (1 2× 1 2—11×1) × 3.14 ≈ 72 (square meters) 3,1,.