# Formation of Numbers

In formation of numbers we will learn the numbers having different numbers of digits.

We know that:

(i) Greatest number of one digit = 9

Smallest number of 2 digits = 10.

(If one is added to 9, we get 9 + 1 = 10).

(ii) Greatest number of 2 digits = 99

Smallest number of 3 digits = 100.

(If one is added to 99, we get 99 + 1 = 100).

(iii) Greatest number of 3 digits = 999

Smallest number of 4 digits = 1000.

(If one is added to 999, we get 999 + 1 = 1000).

(iv) Greatest number of 4 digits = 9999

Smallest number of 5 digits = 10000.

(If one is added to 9999, we get 9999 + 1 = 10000).

Thus, if 1 is added to 9 (greatest 1-digit number), we get 10 (smallest 2-digit number).

If 1 is added to 99 (greatest 2-digit number), we get 100 (smallest 3-digit number).

If 1 is added to 999 (greatest 3-digit number), we get 1000 (smallest 4-digit number).

If 1 is added to 9999 (greatest 4-digit number).

Now we will learn how to use an abacus in number formation

These facts can be expressed on a spike-abacus as follows:

One → 9, 9 + 1 = 10 = One ten

10 → 99, 99 + 1 = 100 = One hundred

100 → 999, 999 + 1 = 1000 = One thousand

1000 → 9999, 9999 + 1 = 10000 = Ten thousand

1-digit numbers:
1, 2, 3, 4, 5, 6, 7, 8, 9.

2-digit numbers:
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, …………., 29,
30, 31, ……., 39, 40, 41,……….., 49, 50, 51,………, 60, 61,………., 69, 70, 71, 72, ……….., 79, 80, 81, ………., 89, 90, 91, ………………......, 99

3-digit numbers:
100, 101, …….., 199, 200, 201, ……, 299, 300, ……., 399, 400, ………, 499,
500, ….., 599, 600, ……, 699, 700, …., 799, 800, 801, ……, 890, ……., 899,
900, 901, ………, 990, 991, ……………, 999.

4-digit numbers:
1000, 1001,……,1099,1100,1101,……,1199,1200,1201,…………,1299,
1300, ……, 1399, 1400, 1401, …….,1499, 1500, 1501,……., 1599, 1600,
1601, ….., 1699, 1700, 1701, ……, 1799, 1800, 1801,………, 1899, 1900,
1901, ......., 1999, 2000, 2001, ……., 2999, 3000, 3001, …….., 3999, 4000,
4001, ……, 4999, 5000, ……., 5999, 6000, ……, 6999, 7000, 7001, ………,
7999, 8000, 8001, ………., 8999, 9000, 9001, ….....,9999.

5-digit numbers:
10000, 10001, ……………………………………………………........., 19999,
20000, 20001, ………………………………………………………….., 29999,
30000, 30001, ………………………………………………………….., 39999,
40000, 40001, .................., 49999, 50000, ………………………….., 59999,
60000, 60001, ……………, 69999, 70000, ……………………… ....., 79999,
80000, 80001, ……………., 89999, 90000, ………………………........ 99999

Now 6-digit numbers begin with 99999 + 1 = 100000, i.e., hundred thousand.

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