How to do the first and third questions of winter vacation homework p88 in the fifth grade of People's Education Edition?

1. Expand the dividend and divisor by 10 times, and the quotient is greater than 3; Then:

10a/ 10b=a/b=3...9

a+b+3+9= 10 ( 1)

a=3b+9 (2)

Bring (2) into (1): 3b+9+b+12 =10b =-4/1a = 3b+9 = 73/9.

2. It is to find the allocation method that the sum of one or more numbers can reach 1, 2,3. . . Every number in 3 1.

The first bag contains 1, so the second bag contains 1 or 2. The classification analysis shows that:

(1). If the second bag contains 1, the third bag can only contain 3; 1+ 1+3=5, and the fourth bag can only hold 6;

1+1+3+6 =11,the fifth bag can only hold 12, while1+1+3+6+1.

(2). If there are two in the second bag, only four in the third bag and only seven in the fourth bag;

1+2+4+7= 14, so the fifth bag can only hold 15, and 1+2+4+7+ 15=29. Therefore excluded;

So the proposition doesn't hold! !