Final answer:
Alice has to pay $14 in total for a hammer and a box of nails after applying a $10 coupon to the original total of $24. This is determined by subtracting the coupon value from the total cost of the items.
Step-by-step explanation:
Alice needs to pay $14 in total after using her coupon. The cost of the hammer and nails before the coupon is $24 ($20 for the hammer and $4 for the nails), and the coupon reduces this amount by $10.
Alice is purchasing two items: a hammer for $20 and a box of nails for $4. The total cost before applying the coupon is the sum of these two amounts, which is $20 + $4 = $24. Alice has a coupon worth $10, which when subtracted from the total cost gives us the final amount she needs to pay. Therefore, the calculation is as follows:
This simple subtraction is an example of a basic arithmetic operation often taught in middle school math.