Based on your picture, I can faintly make out that Maria has one $20 bill, one $10 bill, one $5 bill, two $1 bills, two quarters (25 cents each), three nickels (5 cents each), and three pennies (1 cent each). You can add these together in order to find out the total amount.
The total amount of money that Maria has is $37.68. This will be easier if you've learned about multiplication.
In order to find the total amount that Maria's purchase will cost, all we need to do is add the numbers together. Remember that you need to line up the decimals, which will be pretty simple in this case, since it only has two numbers to the right of the decimal. If you're having trouble with this, you can split it up into whole numbers and decimals, just like we did above with the money:
So, you can see that the number one has gone to the left of the decimal. This means that it must be added to the $28.00, making the total purchase worth $29.73.
We can see that Maria will have enough money for this purchase, since her amount of money is larger than the purchase total. You could subtract the amount that the purchase will be from Maria's money in order to find the exact amount of money Maria will have after the purchase.
For part B, all you need to do is add $12.00 to the total purchase amount, $29.73. In this case only, since you will only be adding 0 to the right side of the decimal, you can just add 12 to 29, then add the decimal on the end. The final purchase amount will be $41.73.
Maria, who only has $37.68, will not have enough money to cover the purchase. To find how much more she needs, you need to subtract the smaller number from the bigger number, as such:
41 – 37 = 4 0.73 – 0.68 = 0.05
Maria will need an additional $4.05 to cover the purchase.
Hope this helped you out! Feel free to ask me any additional questions if you have any. :-)
