Setup: we gots us a cave with kobolds in it! (dwarf fighter at lead, alerting allies). Party consists of fighter, rogue, wizard. Enemy consists of 5 kobolds and an elite kobold for 500xp. The heroes are level 1.
Rogue has been hidden the whole time, since before battle begins. The fighter very unsubtly charges in.
Initiatives: Fighter 15 (+1 and rolled 14), Rogue 20 (17 + 3), Wizard 12 (11 + 1). Kobolds get 8 (6 + 2), Elite kobold gets 19 (18 + 1).
Rogue launches a sling stone at the elite kobold, with advantage for being unseen. 18/12 d20 roll, so 18 + 5 = 23, hitting the elite kobold. 1D8 (7) + 1d6 (6) + 3 = 16 damage.
The elite kobold yelps and collapses dead with a bleeding head wound before he really knows what's happening. The other kobolds screech and raise spears.
The fighter moves in and chops down one of the kobolds with his mighty axe! Since his minimum damage is 3, and the kobolds has 2hp, no roll is really needed. One of the five kobolds drops with its head split in two.
“Step aside, peasants!” the elf proclaims as he strides up next to the fighter, incanting the spell of burning hands. “Watch how it is done!” Each kobold takes 2d4 + 3 damage from the fire, and they scramble for cover against the (1 + 4 + 3) 8 fire damage, halved to 4 even if they pass their dexterity save. The remaining four kobolds go up in flames, thrashing and screaming before they fall to a smoking pile.
The heroes congratulate themselves on their successful ambush of the kobolds. The fighter cleans off his axe, the halfling grabs another stone and goes back to stealth, and the wizard can do that two more times today.
They then try to split 500xp fairly three ways. Which is a far worse challenge than the kobold guard patrol was.