Importance of Brackets

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Using brackets
Brackets help in simplifying an expression that has more than one mathematical operation.
If an expression that includes the brackets is given, then perform the operation inside the bracket and change every thing into a single number. Then carry out the operation that lies outside the bracket.
e.g.
1. (6 + 8) x 10 = 14 x 10 = 140

2. (8 + 3) (9 - 4) = 11 x 5 = 55

Expanding brackets
The use of brackets allows us to follow a certain procedure to expand the brackets systematically.

e.g.

  1. 8 x 109 = 8 x (100 + 9) = 8 x 100 + 8 x 9 = 800 + 72 = 872

  2. 105 x 108 = (100 + 5) x (100 + 8)

                         =  (100 + 5) x 100 + (100 + 5) x 8

                         = (100 x 100) + (5 x 100) + (100 x 8) + (5 x 8)

                         = 10000 + 500 + 800 + 40

                         = 11340.

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1 . which is the smallest 5 digit no. divisible by 35?

The smallest 5 digit number = 10000
The remainder when 10000 is divided by 35  = 10
Therefore , the smallest 5 digit number...

2 . medicine is packed in boxes each weighing 4kg 500g.how many such boxes can be loaded in a van which cannot carry beyond 800kg?

Answer.

Weight of each bag = 4 kg 500 g = 4.5 kg
Capacity of the van = Not more than 800 kg
Number of boxes...

3 . What is the general rule in estimation?

Answer.

The general rule is that we have to round off each number to its greatest place, then add the rounded off numbers.
6157 is

...

4 . what is the consecutive successor of 99

Successor of 99 is 100.

5 . what least number must be added to 1065 to get a number exactly divisible by 33.

32

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