Please leave the following link in the post so we can find the unit module, else replace it with a link to the exact lesson:

useful links

MDN

So I wanted to make sure that I am reading the following example in the correct way:

```
money_in_wallet = 40
sandwich_price = 7.50
sales_tax = .08 * sandwich_price
sandwich_price += sales_tax
money_in_wallet -= sandwich_price
```

So this is the example and will not give me the answer to the final problem but for understanding reasons I am trying to make sure I can read it correctly - so look at the last two lines.

jumping to mdn (the link provided) this is what addition assignment looks like:

// Assuming the following variables

x = 5

y = 10

z = 25

// Number + Number -> addition

bar += 2 // 7

Now back to my example:

are you adding the proportion of sales tax (7.50*0.08) to the actual sandwich price?

Are you subtracting sandwich price from money in wallet?