There are three kinds of animals *** 18, * * with 1 18 legs and 20 pairs of wings (spiders have 8 legs, dragonflies have 6 legs, 2 pairs of wings, cicadas have 6 legs, 1 pairs of wings). How many are there in each of the three animals?

There are 18 in total.

If spiders also have six legs, then the total * * should have 18×6= 108 legs.

There are actually 1 18 legs, and the distance between them is118-108 =10.

So the number of spiders = 10÷(8-6)=5.

Then, the total number of dragonflies and cicadas is 18-5= 13.

If dragonflies also have 1 wings, then * * has13x1=13 wings in total.

There are actually 20 pairs, and the distance between them is 20- 13=7 pairs.

So the number of dragonflies =7÷(2- 1)=7.

Then, the number of cicadas = 13-7=6.