Excel Rounding & Precision: ROUND, MROUND, CEILING, Currency & Floating-Point Traps

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• A wholesale invoice at Juniper Coffee Roasters shows a total that is a cent off the lines you can see. You round every line with ROUND, total the rounded lines, measure the difference to the format-only total and decide which total belongs on the invoice.
• Juniper's stock moves include returns (negative units). You count the boxes to move with ROUNDUP, the full boxes with TRUNC (not INT!), the loose units, and name the function that behaves differently on negatives.
• Set Juniper's shelf prices to the nearest 5 cents and to .99 charm prices, round order quantities up to full cases and bill service jobs in started quarter hours.
• Calculate VAT on a Juniper invoice twice: rounded on every line and once on the invoice total, and measure the cents between the two methods.
• Split a $1,000.00 freight invoice across six cafés by weight. Rounded shares miss the invoice by a cent, so you count the pennies left over and hand them to the largest remainders until the split adds up exactly.
• Juniper books euro invoices in dollars. The booked amounts carry hidden decimals, so a plain = comparison says most payments do not match. You compare at cent level, count the real matches and the cells with hidden decimals.
• Juniper's channel mix rounded to whole percentages adds up to 101%. You round the shares, show the total, adjust the largest share so the mix adds to exactly 100% and chart it as a pie.
• For Juniper's board slide you round monthly revenue to thousands, measure the rounding error per month, build "$48k" labels with TEXT and chart the error so everyone sees how small (or not) it is.