first we add all the fractions:
1/3 + 1/8 + 1/6
to add them, we need the 'least common denominator' (LCD) of the three fractions. LCD is the smallest number that is divisible by 3, 8 and 6.
the LCD of 3, 8 and 6 is 24. then we change all the denominators by 24. to get the new numerator for each, we divide 24 by the original denominator then multiply by original numerator.
for example, 1/3. we divide 24 by 3 and we get 8, then multiply by original numerator (which is 1) and thus the new numerator is 8. and we can say that 1/3 is equivalent to 8/24. applying this to the other two fractions,
8/24 + 3/24 + 4/24
to add fractions, just copy the denominator and add the numerators:
finally, we are asked of the fraction that does NOT play games. therefore, we subtract this from 1 (because 1 or one whole represent the whole class). therefore,
1 - 15/24 = 9/24 or 3/8
hope this helps~ :)