Maths GCSE

Summary 1: Calculations 1 (Numbers)

Decimal System.
A number system using a base of 10.
Thousand (1,000) / hundred (100) / ten 10) / unit (1) / tenth (0.1) / hundredth (0.01) / thousandth (0.001)

Digit
The individual symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 that are used on their own or put together to create a number.

Place Values
The value of a digit depends on its position in the number.

Negative Numbers
A number less than 0.

Rounding
Making a number less accurate, but easier to estimate with.
533.6 = 534 (3 significant figures).

Decimal Places (dp)
The number of digits after the decimal point.
123.456 = 123.46 (2dp)

Significant Figures (sf)
Used to describe the relative importance of of digits in a number.
123.456 = 120 (2sf)

First Significant Figure
The first digit from the left that is not 0.
123000 = 3 is the first significant figure.

Partitioning
Splitting a number into smaller numbers which add to the original number.
127 = 100+20+7

Compensation
One number is rounded to simplify the calculation, then the answer is adjusted to compensate for the original change.
142-38
142-40=102
102+2=104