Students can go through AP 8th Class Maths Notes Chapter 16 Playing with Numbers to understand and remember the concepts easily.
Class 8 Maths Chapter 16 Notes Playing with Numbers
→ Numbers can be written in general form. Thus, a two digit number ab will be written as ab = 10a + b.
→ The general form of numbers are helpful in solving puzzles or number games.
→ The reasons for the divisibility of numbers by 10, 5, 2, 9 or 3 can be given when numbers are written in general form.
→ We are familiar with different number systems like Natural numbers, Whole numbers, Rational numbers, etc. and the properties of those number system.
→ To improve our interest in mathematics we can think of different concepts like addition, division, multiplication etc. in different methods.
→ This is we say “Play with Numbers” which very interesting and thought provoking.
→ A number we write usually (like 27, 52, 108, 260868 etc.) are in usual form.
→ We can express them in generalised form also. Generalised form is nothing but expressing the digits with their number place system.
For
Ex : 23 → im = 2 is in tens place and 3 is in units place.
So 23 can be expressed as (2 × 10) + (3 × 1)
and 57 can be expressed as (5 × 10) + (7 × 1)
and 60 can be expressed as (6 × 10) + (0 × 1)
98 can be expressed as (9 × 10) + (8 × 1)
123 can be expressed as (1 × 100) + (2 × 10) + (3xl)
548 can be expressed as (5 × 100) + (4 × 10) + (8 × 1)
Thus (2 × 10) + (3 × 1),
(5 × 10) + (7 × 1),
(9 × 10) + (8 × 1) all these are in generalised forms.