Hey there! I'm happy to help!
We have $100.75 to spend.
Each spool costs $3, and we have 24 spools.
3×24=72
Each glue costs $1 and we have 7 packages of glue.
7×1=7
We add up these expenses.
72+7=79
And we subtract from our total amount.
100.75-79=21.75
So, Joanna has $21.75 left after buying these things.
Have a wonderful day and keep on learning! :D