Cколько различных пятизначных чисел можно составить из цифр 1, 2, 3, 4, 5, 6, если цифры  в числе не повторяются?

решите цепочку а)Fe=Fe2(SO4)3=Fe=FECL2 б)Si=Mg2Si=Mg(OH)2=MgSO4 в)Si=Ca2Si=Ca(OH)2=CaSiO3 г)Si=Ca2Si=SiH4=SiO2

Помогите пожалуйста очень надо!!

Вставить пропущеное

1. The radio says it _ tomorrow

a)snows b)is snowing c)will snow

2.Of course we know Mary.She is good friend _

a)of theirs b)their c)theirs

3.How _ you get to work?

a)do b)does c)are

4.Look at those black clouds.It _ rain

a)will b)is going c)is going to

5.John works for our firm.-Ready?I _ go and see him at once

a)will b)am going c)going to

6.He _ in the office every day from night to six

a)working b)works c)are working

7.Mary will type the contract very _

a)quickly b)quick c)quicker

8.Do you _ everything for your seminars?

a)have b)have got c)has

9.I _ my old friends for a long time and I'd like them to come to my party

a)hasn't seen b)haven't seen c)doesn't see

10.The academy of Municical Administration _ a modern library and many computers

a)have b)have got c)has

11.Tom has lost his passport again.It's the second time he _ it

a)lose b)lost c)have lost

12.What problems _ you _ at the meeting?

a)will..discussed b)are..going to discuss c)does..discuss

13.The Acadeny _ facilities for physical training in sport clubs

a)provides b)provide c)is providing

14.I have never seen anyone who eats _ exotic food than you do

a)much b)more c)the most

15.We _ an appointment with our partners in Room 308

a)have got b)has c)is having

16.He _ the hotel,took a taxi and drove to the railway station

a)left b)leaves c)has left

17.The manager _ the letter.Can you post it at once?

a)sign b)have sighned c)has signed

18.Are you doing anything special _ the weekend?

a)in b)at c)while

19.When I _ at the railway station, I went to the booking office and bought a ticket

a)arrives b)arrived c)has arived

20.Are these your reports?No,they are _

a)David's b)davids c)of David