[tex] - 3.0 \\ - 5.4 \\ = 8.4[/tex]
For the first one, you take the original temprature -3.0° and add -5.4° which gives you an answer of -8.4°c :)
[tex]3.00 + 5.50 = 8.50 \\ 8.50 \times 7 = 59.50[/tex]
for the second you add the amount for breakfast and lunch, then multiply by 7 days
