To find the best estimate for the amount of money Megan has left, we need to subtract the amount she spent from the amount she initially had.
Initial amount Megan had = $45.12
Amount spent on lunch = $7.89
Amount spent on sunglasses = $21.25
To calculate the estimate for the amount of money Megan has left, we subtract the total amount spent from the initial amount:
Total amount spent = $7.89 + $21.25 = $29.14
Amount of money Megan has left = Initial amount - Total amount spent
Amount of money Megan has left = $45.12 - $29.14
To get the best estimate, we round the initial amount and total amount spent to the nearest whole number:
Rounded initial amount = $45
Rounded total amount spent = $29
Estimate for the amount of money Megan has left = Rounded initial amount - Rounded total amount spent
Estimate for the amount of money Megan has left = $45 - $29
Calculating the estimate gives us:
Estimate for the amount of money Megan has left = $16
Therefore, the best estimate for the amount of money Megan has left is $16.