①(400)厘米:20千米=1/5000
②1厘米:(0.01)千米=1/1000
③1厘米:(6)千米=1/600000
④(30)厘米:600米=1/2000 ⑤(70)厘米:7000米=1/10000
⑥(2)米:2厘米=100/1 ⑦(2.5)米:5厘米=50/1
①(400)厘米:20千米=1/5000
②1厘米:(0.01)千米=1/1000
③1厘米:(6)千米=1/600000
④(30)厘米:600米=1/2000 ⑤(70)厘米:7000米=1/10000
⑥(2)米:2厘米=100/1 ⑦(2.5)米:5厘米=50/1