There are 81 pencils in a box. Abigail removes 5 pencils, Barry removes 2 pencils, Cathy removes 6 pencils and David adds 5 pencils to the box. How many pencils are left in the box?

73 pencils

Step-by-step explanation:

There are 81 pencils in a box.

Abigail removes 5 pencils, thus we have 81-5 = 76 left

Barry removes 2 pencils, it becomes 76-2 = 74

Cathy removes 6 pencils, now it is 74-6 = 68

and David adds 5 pencils to the box,

Now we have 68+5=73 pencils left in the box.