Trying to find Tip amount for Landscaping service workbook.

I've made a Landscaping Price service but I can't get the Tip amount to add up properly. I'm trying to get the Tip amount which is a 6.5% of the cost of the hours worked, ground cover cost and plants cost. As of now I can't figure it out it just prints ($0.00) that's it.

You can't create a variable based upon other variables prior to those variables being defined. Change this section:

'***compute the cost of the hours worked, ground cover, plants, tip and total cost

mathCost = hoursCost + workCost + groundCoverCost
groundCoverCost = groundCoverPrice * numYards
hoursCost = numHours * HOURSWORKED
tipAmount = mathCost * TIPPERCENT
workCost = plantsCost
totalCost = hoursCost + tipAmount + workCost + groundCoverCost

To this:

'***compute the cost of the hours worked, ground cover, plants, tip and total cost

groundCoverCost = groundCoverPrice * numYards
hoursCost = numHours * HOURSWORKED
workCost = plantsCost
mathCost = hoursCost + workCost + groundCoverCost
tipAmount = mathCost * TIPPERCENT
totalCost = hoursCost + tipAmount + workCost + groundCoverCost