Day 73 · Thursday, 15 October 2026
From the archive
Reduce a batch of screen resolutions to their simplest aspect ratio with GCD
A resolution's aspect ratio is just its width and height with every factor they share divided back out, and GCD is what finds that shared factor without you having to guess it.
Task:
Facilities is auditing which displays around the office can show the same content side by side without one of them letterboxing, and that comes down to aspect ratio, not raw resolution. For each display in B2:C5, find the greatest common factor of its width and height, divide both by it to get the simplest whole-number ratio, and join the two results into a label like "16:9". Fill in column D for rows 2 through 5.
The daily challenge is part of Pro
A new exercise every morning, plus every day that came before it — a back catalogue that grows by one a day, whether or not you were here for it.
Every day so far
Recent days
The last 14 days. Today's challenge is free while your streak is alive; Pro opens every past day too.
- 74Day 74 · Friday, 16 October 2026Build a sorted, duplicate-free category breakdown from a ticket log with UNIQUE, SORT and COUNTIFLatest
- Day 73 · Thursday, 15 October 2026Reduce a batch of screen resolutions to their simplest aspect ratio with GCD
- Day 72 · Wednesday, 14 October 2026Project a reserve fund that already holds a balance and gets monthly top-ups with FV
- Day 71 · Tuesday, 13 October 2026Rank sales reps by quarterly revenue and assign a bonus tier with RANK and nested IF
- Day 70 · Monday, 12 October 2026Decide which product returns qualify for auto-approval with OR wrapping two AND conditions
- Day 69 · Sunday, 11 October 2026Pull a payment term off the end of a purchase order number with a varying number of segments
- Day 68 · Saturday, 10 October 2026Roll a due date that lands on a weekend forward to the next business day with WEEKDAY
- Day 67 · Friday, 9 October 2026Look up a consultant's billing rate from a two-way rate grid with INDEX and MATCH
- Day 66 · Thursday, 8 October 2026Turn a route's duration in minutes into hours and minutes with INT and MOD
- Day 65 · Wednesday, 7 October 2026Queue a maintenance team's repair requests by priority without touching the log
- Day 64 · Tuesday, 6 October 2026Find how much loan principal a cargo van's payment plan pays off in its first year
- Day 63 · Monday, 5 October 2026Find the typical closing price and the most common bedroom count in last month's sales
- Day 62 · Sunday, 4 October 2026Count comma-separated labels on a support ticket, and flag the over-tagged ones
- Day 61 · Saturday, 3 October 2026Project each truck's next service date with EDATE, then flag which ones are overdue