The host posts a random three digit number and 6 other number (four random from 1 to 10 and another two from 25, 50, 75 & 100)
Then everyone else would have to use the six number to reach the three digit one using +, -, / and *. The first one to get the number wins, or the one with the closes total, and become the next host.
For example 485 with 3, 4, 6, 9, 25, 100.
4*100 = 400
3*25 = 75
400 + 75 = 475
475 + 9 = 484.
I will start:
Total to reach: 524
Number to use: 2, 3, 7, 9, 50 & 100