Appropriate subnet address ranges

I have been given IP addresses from 129.196.140.0 thru 129.196.143.255. From those addresses I must create 6 subnets to accomodate segments with as few as 2 NICs to as many as 135 workstations. And I need to figure out the appropriate subnet mask for each address range. If I use 8 bit slots for host addresses (to accomodate the 135 workstation subnet), then I only have 4 subnets (x.y.140.0, x.y.141.0, x.y.142.0 and x.y.143.0). I can’t figure out how to get 6 subnets and still have enough host IDs for the 135 workstation subnet. allamp@foxinternet.net