1。 The remainder is 1. 16 has a power mantissa of 2,3,6; 17 has a quadratic mantissa of 9, a cubic mantissa of 3, a quartic mantissa of 1 and a quintic mantissa of 9. 1988 is divisible by 4, so its mantissa is1; The quadratic mantissa of 19 is 1, and the cubic mantissa of 9 1989 is odd, so its mantissa is 9. 6+ 1+9= 16. If you divide by 5, the remainder is 1.

2. Through the method of back calculation, we can know that: A: 950ml; B: 5 10 ml; C: 460ml.

3. After six digits are multiplied by 4080, the mantissa should be 0, and the product is between 4080000000 and 408000000-4080. Therefore, one of the six consecutive natural numbers must have a mantissa of 5 or 0. The result of product analysis is that these six digits are 34, 35, 36, 37, 38, 39 and 2 19 respectively.

(1): Two isosceles triangles can be combined into a square, and four squares can be combined into a big square, so nine such squares can be combined into a big square with an area of 0.5*2*4*9=36.

(2)*** 10