First you want to know that you want to subtract the bird seed Jackie got (2 2/3 and 1/4) by the total Jackie bought (5 1/2).
Now set up the equation as 5 1/2 - (2 2/3+ 1/4). Now you need to realize that the fractions are not the same and need to be changed to similar denominators. 2 can be changed to any even denominator so it matters less to what we change it to, so let's focus on the bird seed Jackie used and convert it. 2/3 and 1/4 can be changed into 12's so multiply on the numerator and denominator to get these values. 2/3 would then become 8/12 and 1/4 would become 3/12. 1/2 would then also become 6/12.
Now that we have changed the fractions you want to change the expression to 5 6/12 - (2 8/12+ 3/12). Now add the values in the parentheses to get 5 6/12 - (2 11/12). Now to make this easier add more 12's to 5 6/12 by putting it to 4 18/12. the new equation will be 4 18/12 - 2 11/12, finally subtract from from the same types of numbers: 4-2= 2 18/12-11/12= 7/12. The answer would be 2 7/12.
As Louis is only leaving a 20% tip on the pretax bill, this means he's leaving 20% of $27.62 The best thing to do is to find 10% and double it. 27.62/10= 2.76 (as it rounds down) 2.76*2= 5.52 Therefore, you've got to add $5.52 to $27.62 $5.52+$27.62= $33.14 Hope this helps :)
