To add fractions, we need to find a common denominator first. In this case, the common denominator is 63.
(13/27 + 2/9) - (11/21 + 1/7)= (137 + 221)/ (277) - (113 + 19)/(213)= (91 + 42) / 189 - (33 + 9) / 63= 133 / 189 - 42 / 63= (133 - 126) / 189= 7 / 189
Therefore, (13/27 + 2/9) - (11/21 + 1/7) = 7/189.
To add fractions, we need to find a common denominator first. In this case, the common denominator is 63.
(13/27 + 2/9) - (11/21 + 1/7)
= (137 + 221)/ (277) - (113 + 19)/(213)
= (91 + 42) / 189 - (33 + 9) / 63
= 133 / 189 - 42 / 63
= (133 - 126) / 189
= 7 / 189
Therefore, (13/27 + 2/9) - (11/21 + 1/7) = 7/189.