We use numbers ever day and every time for calculating rates and other purpose. The two things and the same kind are attributed numerical values, able compare them. Comparison is expressed in phrases like are` greater than and less than’ to multiple of Etc.

See on example, a familiar situation in cricket game which Ganesh has scored 17 runs, while Rajesh earned 51 runs in an inning.

1) Rajesh scored 34 runs more than Ganesh or Ganesh scored 34 runs less than Rajesh. Or,

2) Rajesh scored three times as many runs as ganesh or we say that ganesh scored only one third of runs made by Rajesh.

When compare in the way as two, are finding the ratio between the two numbers. In short, the ratio is between two quantities A and B.

Find ratio of the first number to the second one, find ` what of second number is the first number; and this is do divined the first number by the second one.

17 1

Modal: the ratio of 17 to 51 = ___ = ___

51 3

50 5

The ratio of 50 to 30 = ___ = __

30 3

The phrase the ratio of 17 to 51 is written as 17:51 and read as 17 is to 51.

Comparing two quantities in terms of Ratio bear in the mind.

A) The two quantities must be of the same kind.

B) The units’ measurement of the quantities must be the same.

C) The ratio denotes how many times one quantity of other is, it is a pure number.

Example;

4m: 80cm = 400cm: 80cm = 5:1

1 hr 30min : 2hrs 15 min = 90 min : 135 min = 2:3

Involved numbers in ratio are called its `terms’.

The common factor of the two terms 105 and 135, obtain the lowest form of the ratio 105:135 as 7:9.

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