I am getting an perform arithmetic (add) on Instance and number  error can anyone help please?

The code error looks like this:   17:01:23.444 ServerScriptService.Remotes:10: attempt to perform arithmetic (add) on Instance and number  -  Server  -  Remotes:10 The code looks like this: player.leaderstats.Strength.Value = player.leaderstats.Strength + 15 * player.leaderstats.Rebirths.Value + 1

Please help.