Mental Maths

Mrs Idle says: "Mental maths guys open it up!"
"Aleks," she called me.
"Y-e-s, Mrs Idle?"
"I am not happy with you, where is your mental maths, we are starting in a minute," she yells.
"I'll c-h-e-c-k in my bag," I added.
A few minutes later I found it!!!
I was happy!!!