Hours × rate + extras
For a service estimate, select the hours input, multiply by a fixed hourly rate, then add the extras choice. If Hours is 4, the rate is 85 and the selected extra is 60, the result is 400. Leave extras unselected and their sum is zero.
Parentheses decide what repeats.
(Package + extras) × quantity and Package × quantity + extras mean different things. With a package of 100, extras of 20 and quantity 3, the first gives 360; the second gives 320. Choose the version that matches how you charge.
Multiple selected values are added together.
A multiple-choice block contributes the sum of the numeric values on selected options. Selecting extras worth 50 and 90 gives the formula a value of 140. It does not automatically multiply the options together. Put a quantity multiplication in the Formula when you want one.
A 10% discount means multiply by 0.9.
In Conditional adjustments, choose the condition that earns the discount and multiply the current amount by 0.9, or use the percentage-decrease control. Subtracting 10 subtracts ten currency units, not ten percent. Two successive 10% discounts multiply by 0.9 twice, giving a 19% total reduction.
Reuse a subtotal without referring back to yourself.
One Result can use another calculation as an input. For example, Monthly value = Hours saved × Hourly value. The Hours saved calculation must not depend on Monthly value in return. Give intermediate calculations clear names so the dependency remains easy to follow.
Separate the value from its display format.
Currency formatting changes how a number is displayed, not its value or exchange rate. Percent formatting expects a fraction: 0.25 becomes 25%. If a slider supplies 25 as a percentage, divide it by 100 in a formula before multiplying another amount.