To simplify the expression, we first need to perform the operations within each fraction.
6 3/4 ÷ 9 = 27/4 ÷ 9 = 27/4 * 1/9 = 27/36 = 3/4
24 ÷ 6/7 = 24 * 7/6 = 168/6 = 28
1/9 ÷ 4/21 = 1/9 * 21/4 = 21/36 = 7/12
Now we substitute these results back into the expression:
3/4 + 28 - 7/12= 9/12 + 28 - 7/12= 32 - 7/12= 384/12 - 7/12= 377/12
Therefore, the simplified expression is 31 5/12.
To simplify the expression, we first need to perform the operations within each fraction.
6 3/4 ÷ 9 = 27/4 ÷ 9 = 27/4 * 1/9 = 27/36 = 3/4
24 ÷ 6/7 = 24 * 7/6 = 168/6 = 28
1/9 ÷ 4/21 = 1/9 * 21/4 = 21/36 = 7/12
Now we substitute these results back into the expression:
3/4 + 28 - 7/12
= 9/12 + 28 - 7/12
= 32 - 7/12
= 384/12 - 7/12
= 377/12
Therefore, the simplified expression is 31 5/12.