Answer:
3/10
Step-by-step explanation:
Numbers Given are:
1 1/2, 2 1/2, 1 2/3, and 2 5/6
The result at the end of all the math is 2 5/6.
1 2/3 + 2 5/6 = 4 1/2
Divide 4 1/2 by 1 2/3 to get 2 7/10.
Subtract 2 2/3 from 2 7/10 to get 1/5.
Multiply 1/5 by 1 1/2 to get 3/10.
So the number they thought of was 3/10.