2 — math

2 is the natural number following 1 and preceding 3.

In mathematics

2 is the smallest prime number.
A number is divisible by 2 if it's an even number, this means that in base-10, the last digit should be even.
It is one of the only eight digits that is not in the binary computer system, the other seven are 3, 4, 5, 6, 7, 8, and 9.
Decanumbers with 2 in it are 12, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, and 92.
Two's divisibility rule depends on the base:
- If the base number is odd, all the digits of even numbers should add to an even number.
- If the base number is even, the last digit should be even.

Multiplication
-	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
2×x	2	4	6	8	10	12	14	16	18	20	22	24	26	28	30	32	34	36	38	40

Division
-	1	2	3	4	5	6	7	8	9	10
2÷x	2	1	0.66667	0.5	0.4	0.333333	0.285714	0.25	0.222222	0.2
x÷2	0.5	1	1.5	2	2.5	3	3.5	4	4.5	5

Exponentiation
-	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
2^x	2	4	8	16	32	64	128	256	512	1,024	2,048	4,096	8,192	16,384	32,768
x²	1	4	9	16	25	36	49	64	81	100	121	144	169	196	225

Computers use base-2 to operate.
Humans have 2 eyes.
Humans have 2 hands.
Humans have 2 arms.
Humans have 2 ears.
Humans have 2 legs.
Humans have 2 feet.
Humans typically have 2 sets of chromosomes.
Cherries typically come in pairs.
Socks and shoes come in pairs.
Gloves come in twos.
2-factor authentication offers 2 layers of security, so you can browse more safely.
Two imperial pints make one quart.
Two imperial cups make one pint.

2's value means: