Parity (mathematics)

Parity is a mathematical term that describes the property of an integer's inclusion in one of two categories: even or odd. An integer is even if it is 'evenly divisible' by two and odd if it is not even. For example, 6 is even because there is no remainder when dividing it by 2. By contrast, 3, 5, 7, 21 leave a remainder of 1 when divided by 2. Examples of even numbers include −4, 0, 8, and 1738. In particular, zero is an even number. Some examples of odd numbers are −5, 3, 9, and 73. Parity does not apply to non-integer numbers.

A formal definition of an even number is that it is an integer of the form n = 2k, where k is an integer; it can then be shown that an odd number is an integer of the form n = 2k + 1. This classification applies only to integers, i.e., non-integers like 1/2, 4.201, or infinity are neither even nor odd.

The sets of even and odd numbers can be defined as following:

Even 

Odd 

A number (i.e., integer) expressed in the decimal numeral system is even or odd according to whether its last digit is even or odd. That is, if the last digit is 1, 3, 5, 7, or 9, then it is odd; otherwise it is even. The same idea will work using any even base. In particular, a number expressed in the binary numeral system is odd if its last digit is 1 and even if its last digit is 0. In an odd base, the number is even according to the sum of its digits – it is even if and only if the sum of its digits is even.

Second grade

Second grade (called Grade 2 in some regions) is a year of primary education in many nations. Second grade is the second school year after first grade. Students are traditionally 7–9 years old, depending on when their birthday occurs.

In mathematics, students are taught place value to tens, hundreds or thousands, and renaming with addition and subtraction. Measurement is extended to the meter, foot, yard, kilogram, pound, and pint. Measurement of time and temperature in Fahrenheit and Celsius is also emphasized as well. Usually multiplication and division is introduced towards the end of the school year but not emphasized. Another skill students practice is counting money and making change. Positive and negative numbers are introduced, but not added and subtracted. These values are generally introduced in temperature. Addition and subtraction facts are practiced throughout the year. Students also learn about plane and solid shapes in geometry and explore how they are apparent in our everyday lives. Some second grade topics in math can be explored at the following website.

Odds and evens

Odds and evens, also known as swords, choosies, pick, odds-on poke, or bucking up, is a hand game played between two people, used to decide an issue. This zero-sum game, a variation of the ancient Morra and par-impar, is played internationally, especially among children.

The individuals prepare by deciding who will be assigned odds and who will be evens. Then, one or both people say "One, two, three, shoot!!" or "one, strikes, three, shoot!" As the word "shoot" is said, the two people quickly and simultaneously thrust a fist into the center, extending either an index finger, or both the middle and index finger, indicating one or two. The sum total of fingers displayed is either odd or even. If the result is odd, then the person who called odds is the victor, and can decide the issue as he or she sees fit. Often, the participants continue to shoot for a best two out of three.

In a single game, the chance of either person winning is 50%.

See also

All the Time

All the Time may refer to:

Odd and Even

Odd and Even is a solitaire card game which is played with two decks of playing cards. It is so called because the building is done in twos, resulting in odd and even numbers.

First, nine cards are dealt in three rows of three cards each, all laid out, to form the reserve.

As they become available, one Ace and one Deuce (or Two) of each suit are placed in the foundations, each to be built up by suit in twos. Therefore, the order of building should be as follows:

On the Aces: 3-5-7-9-J-K-2-4-6-8-10-Q
On the Deuces: 4-6-8-10-Q-A-3-5-7-9-J-K

The nine cards in the reserve are all available for play, to be built on the foundations (no building on the reserve). Gaps in the reserve are immediately filled with cards from the wastepile, or if there is no wastepile yet, the stock.

When play goes to a stand still, the stock is dealt one a time. A card from the stock that cannot be built on the foundations is placed on the wastepile, the top card of which is available for play.

One redeal is allowed. To do this, the player can pick up the wastepile and turn it over to be used as the new stock.