Question

Alex has $450 in her savings account.She decides to deposit $13 every week for 6 weeks and then she buys 7 tickets for a haunted house that cost $11.25 each.Create a number sentence to model this scenario.

Answer 1

$450+(13\cdot6)=450+78=528$ - the amount Alex will have in her savings account after depositing $13 for 6 weeks in a row
$\\528-(11.25\cdot7)=528-78.75=449.25$ - the amount Alex will have in her savings account after buying 7 tickets worth $11.25 each

Answer 2

First, you would create an equation for this problem (I think that is all you have to do, but I'll solve it anyway).
($13 × 6) + $450 - ($11.25 × 7)

Now, using the order of operations (PEMDAS), you solve it. 
($13 × 6) + $450 - ($11.25 × 7) = $449.25

Alex has $449.25 in her savings account. 

I hope this helps!