1, 80 divided by 16 equals 5 cm 80 times one third equals 80 cm 2.

2、4? 3 divided by 6 equals 32 square centimeters.

Second,

1× (1cm is equivalent to 30m, and the scale is 1: 3000).

2、×

3.√ (Assume that 1/6 of number A and 1/5 of number B are equal to X, and number A is equal to x divided by 1/6. The number b is equal to x divided by 1/5)

Third,

1、3. 14×3×2+3. 14×(3/2)? =25.905 M？

2、 1/3×3. 14× 1.5? ×1./kloc-0 /×1.4 = 3.6267 is about 4 tons.

3、 100/2*3= 150

4、

4000000×20=80000000 (cm)

8000000000 cm =800 km

(800-8*55)/8=45