Great question! Let's break it down for both sides of the ruler, showing exactly how many times each day of the week appears in the gaps, and which gaps they fall on.
1. Imperial Side (12-inch ruler, 1/16" increments)
Total gaps: 192
Days of the week: 7
Full weeks in 192 gaps: 192 ÷ 7 = 27 weeks, remainder 3
So, after 27 complete cycles (27 × 7 = 189), there are 3 extra gaps.
How Many of Each Day?
Sundays: 27 (one per week) + 1 (first extra gap) = 28
Mondays: 27 + 1 (second extra gap) = 28
Tuesdays: 27 + 1 (third extra gap) = 28
Wednesdays: 27
Thursdays: 27
Fridays: 27
Saturdays: 27
Where Do They Fall?
Sundays: Gaps 1, 8, 15, ..., 190 (every 7th gap, starting at 1), plus gap 190
Mondays: Gaps 2, 9, 16, ..., 191, plus gap 191
Tuesdays: Gaps 3, 10, 17, ..., 192, plus gap 192
Wednesdays: Gaps 4, 11, 18, ..., 189
Thursdays: Gaps 5, 12, 19, ..., 190 (but 190 is already counted as Sunday in the extra cycle, so last is 188)
Fridays: Gaps 6, 13, 20, ..., 189 (last is 186)
Saturdays: Gaps 7, 14, 21, ..., 189 (last is 187)
Or, more simply:
Sundays: Gaps where (gap number - 1) mod 7 = 0
Mondays: (gap number - 2) mod 7 = 0
...and so on.
2. Metric Side (30-cm ruler, 1 mm increments)
Total gaps: 300
Full weeks in 300 gaps: 300 ÷ 7 = 42 weeks, remainder 6
How Many of Each Day?
Sundays: 42 + 1 (first extra gap) = 43
Mondays: 42 + 1 = 43
Tuesdays: 42 + 1 = 43
Wednesdays: 42 + 1 = 43
Thursdays: 42 + 1 = 43
Fridays: 42 + 1 = 43
Saturdays: 42 (no extra gap for Saturday)
Where Do They Fall?
Sundays: Gaps 1, 8, 15, ..., 295, plus gap 295
Mondays: Gaps 2, 9, 16, ..., 296, plus gap 296
Tuesdays: Gaps 3, 10, 17, ..., 297, plus gap 297
Wednesdays: Gaps 4, 11, 18, ..., 298, plus gap 298
Thursdays: Gaps 5, 12, 19, ..., 299, plus gap 299
Fridays: Gaps 6, 13, 20, ..., 300, plus gap 300
Saturdays: Gaps 7, 14, 21, ..., 294
Summary Table
Day Imperial (192 gaps) Metric (300 gaps)
Sunday 28 43
Monday 28 43
Tuesday 28 43
Wednesday 27 43
Thursday 27 43
Friday 27 43
Saturday 27 42
How to Find Where Each Day Falls
For any gap number
n
n:
Day = (n - 1) mod 7
0 = Sunday
1 = Monday
2 = Tuesday
3 = Wednesday
4 = Thursday
5 = Friday
6 = Saturday
If you want a specific list of gap numbers for each day, or a visual chart, just ask!