Home › Weekday Before › If today is Thursday, 100 days before
Quick Answer
What is Thursday − 100 days?
These sentences all describe the same result:
If today is Thursday, 100 days before was Tuesday
100 days before Thursday is Tuesday
Thursday − 100 days = Tuesday
The weekday 100 days before Thursday is Tuesday
Detailed Math (Step-by-Step)
We show the whole operation clearly (modulo 7).
Step 1: Find the remainder
Since weekdays repeat every 7 days: days mod 7 tells us how many steps to move backward.
| Days | 100 |
|---|---|
| Divide by 7 | 14 remainder 2 |
| Remainder | 2 |
Step 2: Move backward 2 day(s)
Start at Thursday and count backward 2 step(s).
| Step | Weekday |
|---|---|
| 0 | Thursday (start) |
| 1 | Wednesday |
| 2 | Tuesday (result) |
Quick Lookup Table
Common values going backward from Thursday.
| Days before Thursday | Weekday | Remainder (mod 7) |
|---|---|---|
| 0 | Thursday | 0 |
| 1 | Wednesday | 1 |
| 2 | Tuesday | 2 |
| 3 | Monday | 3 |
| 4 | Sunday | 4 |
| 5 | Saturday | 5 |
| 6 | Friday | 6 |
| 7 | Thursday | 0 |
| 8 | Wednesday | 1 |
| 9 | Tuesday | 2 |
| 10 | Monday | 3 |
| 14 | Thursday | 0 |
| 21 | Thursday | 0 |
| 28 | Thursday | 0 |
| 30 | Tuesday | 2 |
| 100 | Tuesday | 2 |
Tip: Any number of days that differs by a multiple of 7 lands on the same weekday.
Instant Calculator
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More “Weekday Before” Examples
Check other weekday calculations going backward in time.