How to make an unboxing system ?

Hello I'm currently working on a game, and I need to make an unboxing system. When unboxing, you will get items (tools) based on their rarities.

There are 5 rarities : **- Common (50%)

• Uncommon (30%)
• Rare (15%)
• Super-rare (4%)
• Ultimate (1%)**

This is not a request site, though I will provide you with the basic ideas for an unboxing system. Create tables for each rarity with the corresponding tools in each one. Create a randomizer that picks a random number between 1 and 100. If the number is 1-50, then it is common, 51-80 is uncommon, 81-95 is rare, 96-99 is super rare, 100 is ultimate. Then use another number randomizer to pick a number between 1 and the number of tools corresponding to the randomly selected rarity.