IP range in firewall

I am trying to add a custom allow rule in the firewall for a range of IPs from -, what exactly am I supposed to enter in the source box? I believe I have to add two separate rules for 102 and 103, and I put /24 at the end of both, is this correct to get the whole range of IPs?

Fortunately for you that range can be summarised as

subnet calculator - Google Search

O.K. great thanks.