Let's use an example. If Nathaniel earned $15 on Tuesday, and earned $10 less on Wednesday, then 15-10 = 5 dollars is the amount he earns on Wednesday.
Now let's say he earned $27 on Tuesday, and still earned $10 less the next day, meaning that he earns 27-10 = 17
Whatever he earns on Tuesday, subtract off 10. That's the rule to follow for this problem.
(amount earned on Tuesday) - 10 = amount earned on Wednesday
If n reprsesent the placeholder for "amount earned on Tuesday", then we can rewrite that equation as
amount earned on Wednesday = n - 10
In short, whatever 'n' is, subtract 10 off it. In the examples above, I used n = 15 and n = 27.
note: the order of subtraction matters. The expression n-10 is not the same as 10 - n. If you subtract in the wrong order you may get a negative value (eg: 10 - 17 = -7), but he can't earn a negative amount of dollars.
