#pickpocketing

:(

"You pilfer a few amateurly drawn charcoal sketches from your victim."

"Your victim's pockets were full of leaves, none of which are particularly rare or unusual."

"You find an unmailed letter to your victim's mother, describing the petty crime common to the area."

"You pilfer a few pebbles your victim has unaccountably been collecting."

Compare the two below, with and without gloves that gives a +1:

It seems that the game first takes into account modifiers inherent to the character as well as modifiers from items.

+4 Proficiency +4 Expertise in Sleight of hand +5 DEX modifier +1 Sleight of Hand from gloves

+14 total. Then, it subtracts that from the DC, which is 21, to get 7 as the Target number, which is what you need to beat with your dice and the rest of the modifiers you have.

In the second image I took off the gloves. The DC is 20, but the Target is still 7, which means the total is now +13 without the gloves.

So it seems the Target is the number you have to beat with your dice plus I think 'variable' modifiers like +1d4 Guidance and 'conditional' modifiers like Astarion's +1 Happy. Examples with both below