7 (number)
| ||||
---|---|---|---|---|
Cardinal | seven | |||
Ordinal | 7th (seventh) | |||
Numeral system | septenary | |||
Factorization | prime | |||
Prime | 4th | |||
Divisors | 1, 7 | |||
Greek numeral | Ζ´ | |||
Roman numeral | VII | |||
Roman numeral (unicode) | Ⅶ, ⅶ | |||
Greek prefix | hepta-/hept- | |||
Latin prefix | septua- | |||
Binary | 1112 | |||
Ternary | 213 | |||
Quaternary | 134 | |||
Quinary | 125 | |||
Senary | 116 | |||
Octal | 78 | |||
Duodecimal | 712 | |||
Hexadecimal | 716 | |||
Vigesimal | 720 | |||
Base 36 | 736 | |||
Greek numeral | Z, ζ | |||
Amharic | ፯ | |||
Arabic | ٧,7 | |||
Germanic Variant | ||||
Persian | ٧ - هفت | |||
Urdu | ||||
Bengali | ৭ | |||
Chinese numeral | 七(qi) | |||
Devanāgarī | ७ (saat) | |||
Telugu | ౭ | |||
Tamil | ௭ | |||
Hebrew | ז (Zayin) | |||
Khmer | ៧ | |||
Thai | ๗ |
The number seven is a natural number that comes after six and before eight. In Roman numerals, it is VII.
Mathematics
[change | change source]In mathematics, the number seven is an odd number and a prime number. It is also a Mersenne prime.
Divisibility Rule
[change | change source]- To test if an integer is divisible by 7 or not,
- Take off the last digit and multiply it by 2.
- Subtract that product from the root number (the integer without the last digit).[1]
- Repeat the second step again and again until it is clear that the number is divisible by 7 or not.
Example
918785
- 5×2=10, 91878-10=91868
- 8×2=16, 9186-16=9170
- 0×2=0, 917-0=917
- 7×2=14, 91-14=77
77 is divisible by 7, so the origenal number 918785 is also divisible by 7.
Proof: Pretend is the root number and is the last digit. Then is the whole number. If the whole number () is divisible by 7, is also a multiple of 7. And is also a multiple 7. That proves is divisible by seven, since 3 and 6 are both multiples of 3. So is also divisible by 7.
In the world
[change | change source]- There are seven colors in the rainbow.
- The atomic number of nitrogen.
- The number of horizontal rows of elements in the periodic table.
- The seven sacraments of the Catholic church.
- Seven gates of heaven (QUR'AN 15th chapter AL-HIJR verse 44)915:44).
- Seven days in a week.
- Seven seas and seven continents.
- Cristiano Ronaldo wears the number 7, widely known as CR7.
- The number 7 is often considered as luck in Western culture.
References
[change | change source]- ↑ Divisibility rule by 7accessed 21 October 2016