SIMPLE LOGIC mistake

Here is a question for students relating the logic with gates and truth table:

Given the following logic gates circuit:

Simple gate
Simple Logic Gate

(a) Find the boolean expression.

Most students know how, it is OUTPUT Y = (INPUTB + INPUTA)*INPUTB

(b) Find the truth table.

Most students did it, it is:

INPUTA INPUTB OUTPUTY
0 0 0
0 1 1
1 0 0
1 1 1

(c) Simplify the output expression. Here is the problem. Most of the students did not pay attention to the truth table when simplifying the expression. If they can see OUTPUTY has the 0101 as INPUTB, they could have just said Y=B without going through the step by step of simplying. Just that simple.

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