Hello! Im trying to use the document as a study reference. I don't understand how the number for supplies is calculated.

Hello! Im trying to use the document as a study reference. I don't understand how the number for supplies is calculated.. in this problem it would be the sections such as in the

T chart account for jan 31 a.

supplies amount debited on the unadjusted trial balance

supplies amount debited and created for the adjusting journal entry

could you explain how this number is found?