=320×5/32×22/5
= 220km
2,66+66× 2/33 = 7 billion;
3. Original price = 320 ÷ (1-68%) =1000 yuan;
4, can't see clearly;
5、4/5× 1/7÷2/5
=4/5× 1/7×5/2
=2/7;
1/9×9÷( 1/9×2 1)
= 1/9×9÷ 1/9÷2 1
= 1/9×9÷ 1/9÷2 1
= 1×9× 1/2 1
=3/7;
4.5x+x= 12/ 17
Solution:11/2x =12/17.
x = 12/ 17×2/ 1 1
x = 24/ 187;
x÷7/8= 1/4+0.25
Solutions; x×8/7= 1/4+ 1/4
x= 1/2×7/8
x=7/ 16