MathematicsBeginner

Common years and leap years

Leap years: divisible by 4, not by 100 unless by 400

Estimated time · 8 min 9 Content blocks

Core concepts

Formulas

闰年  ⟺  4∣y  (整百年需 400∣y)\text{闰年} \iff 4\mid y \;(\text{整百年需 } 400\mid y)

Worked example

Example
Solution

Worked example

Worked examples
Example
Solution steps
  1. 1
  2. 2
Answer

Worked example

Worked examplesVariant 1
Example
Solution steps
  1. 1
  2. 2
Answer

Worked example

Worked examplesVariant 2
Example
Solution steps
  1. 1
  2. 2
Answer

Exercises

Fill in the blank

Prerequisites

Dates, long months and short months8 min
Practice set
Answered 0 / 6
1Fill in the blank

Tip

2Fill in the blank

Tip

3Fill in the blank

Tip

4True / False

Tip

5True / False

Tip

6True / False

Tip

Results are not saved — this session disappears when you leave.
AI DO LEARN

Science, made explorable.

5 Disciplines·6 Levels·647 Knowledge points

© 2026 AI DO LEARN. All rights reserved.

Original explanations, diagrams and code may not be republished without permission; please credit the source when quoting.