User:Adefebisara/Sample page

= Mathematics Dictionary =

A
Abacus 

An abacus has beads that slide on rods. It can be used to count, add, subtract, multiply and more.

• the column on the far right is for ones (1,2,3,...)

• the next column is for tens (10,20,30,...)

• the next column is for 100s (100, 200, 300,...)

Abscissa 

The horizontal ("x") value in a pair of coordinates. How far along the point is.

Always written first in an ordered pair of coordinates such as (12, 5).

In this example, the value "12" is the abscissa.

(The second value "5" shows how far up or down and is called the Ordinate)

Absolute Error 

The difference between the actual and measured value.

Shown as a positive value.

Example: When your instrument measures in "1"s, then any value between 6½ and 7½ is measured as "7", so the absolute error is ½.

Absolute Value 

How far a number is from zero.

Examples:

6 is 6 away from zero, so the absolute value of 6 is 6

−6 is 6 away from zero, so the absolute value of −6 is 6

In other words it is the magnitude or size of a number, no negatives allowed.

The symbol "|" is placed either side to mean "Absolute Value", so we write: |−6| = 6

Acceleration 

How fast velocity changes.

Usually measured as m/s2 ("meters per second squared").

Example: going from 5 m/s (5 meters per second) to 6 m/s in exactly one second is an acceleration of 1 meter per second per second.

And two lots of "per second" becomes "per second squared".

So the acceleration is 1 m/s2.

Accuracy 

How close a measured value is to the actual (true) value.

Acre 

A US Standard Unit of area, usually used to measure land.

1 acre = 4,840 square yards.

1 acre is about 0.4 hectares in the Metric system, or exactly 4,046.8564224 square meters.

 Acute Angle 

An angle less than 90° (90° is called a Right Angle)

Try different angles below: