Days
Weekday cycle; count days forward and backward.
Days
Days of the Week
What you'll learn
- Know the 7-day cycle: Mon → Tue → … → Sun → Mon.
- Count forward/backward for tomorrow, yesterday, day after.
- Use remainder (÷ 7) for dates far in the future.
- Distinguish weekdays (5) from weekend (2).
Key concepts
Level 1 — Cycle
Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday — then repeat.
Level 2 — +1 / −1 day
Wed → Thu (tomorrow); Wed → Tue (yesterday).
Level 3 — Remainder trick
After n days from today: find n mod 7, add to start day.
+7 days → same weekday.
Level 4 — Indian context
School is closed on Sunday. If today is Friday before a Monday exam, count study days.
NCERT anchor: CBSE Class 4 logical reasoning; Math-Magic 4 Ch 4 — Tick-Tick-Tick (days and weeks)
Worked example
Today is Wednesday. Day after 10 days?
Step 1 — 10 ÷ 7 → remainder **3**.
Step 2 — Wed + 3 = Sat.
Answer: **Saturday**
Today is Sunday. What day was 8 days ago?
Step 1 — 8 ÷ 7 → remainder 1 (or 8 = 7+1).
Step 2 — Sunday − 1 = Saturday.
Answer: **Saturday**
Common mistakes
| Mistake | Why it happens | Fix |
|---|---|---|
| Counting 8 days as one week | Week = 7 days | 7 days later = same weekday |
| Forgetting Sun → Mon wrap | Not cycling at boundary | After Sunday comes Monday |
| Using 30 mod 7 without reducing | Large n not simplified | Divide by 7 and use remainder only |
| Day before yesterday = −1 | Two days back | Day before yesterday = −2 days |
Quick check
- Tomorrow if today is Fri?
- 7 days after Monday?
- How many weekdays in a week?
- Stretch: Republic Day is on a Sunday. What weekday is it 100 days later? (100 mod 7 = 2 → Tuesday)
Revision tip: Write weekdays in a circle — arrow forward +1, count remainder steps for big jumps.
Open the Practice tab for graded questions on Days of the Week.
Key Takeaways (TL;DR)
- What you'll learn
- Key concepts
- Worked example
- Common mistakes
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