I have spreadsheet which has 3 columns

A B C
1 Acct No Account Amount
2 D12 XX1 732.50
3 XX2 10,451.12
4 D13 XX3 52,741.51
5 D14 XX4 289.86
6 XX5 7,654.12
7 D15 XX6 95,785.32
8 XX7 2,367.49
9 XX8 32,965.74
10 D16 XX9 65,874.36

What i would like to do is produce 2 diferent sum amount based on a diferent
criteria.

firstly: I want to sum column C only the amounts where there is no account
no.
basically =sumif(a2:c10, "if the corresponding value in column a is
blank",c2:c10)

secondly: sum the amounts in column c in between £5,000 and £50,000

Thanks In advance

Hervinder