You saw a shirt worth kes 97. You did not have cash at hand and therefore you borrowed kes 50 from your father and kes 50 from your mother totalling kes 100. Because the shirt costs kes 97, you got change for kes 3. You chose to reduce the debt by returning kes 1 to your dad and kes 1 to your mum remaining with kes 1. That means you owe dad kes 49 and mum kes 49 i.e kes 98 total. Adding kes 98 to the kes 1 in your hand comes to kes 99. Where is the missing kes 1?

Nothing missing
100-97(3)-2 (1)+1+98=100

I find this easier to think about in reverse. You borrow KES 100 from your mother and father. But then you know you need only KES 97 to buy a shirt. To reduce your debt, you return KES 2 straight away. That leaves you with a debt of KES 98, the exact amount of money you have at hand. When then you spend KES 97 on a shirt, you are left with KES 1. How then can there be a missing KES 1? No money is missing.

Three people check into a hotel. They pay $30 to the manager and go to their room. The manager finds out that the room rate is $25 and gives the bellboy $5 to return to the guests. On the way to the room the bellboy reasons that $5 would be difficult to split among three people so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1. So they paid $9 each, totaling $27. The bellboy has another $2, adding up to $29.

They paid 27 in total... 25 to the hotel and involuntary tip of 2.
25+2=27

What type of shirt was it? Was it new or mtush?