- Between two numbers
- the one with more number of digits is greater. For instance, 842 > 42.
- if the number of digits in the two numbers is the same, the number whose leftmost digit is larger is the greater one. For example, 6215 > 1256.
- if the leftmost digit is the same, then we compare the next digit and so on. Fr example, 6521 > 6512 > 6251 > 6215
- Order of arrangement
- Ascending order refers to the arrangement from the smallest to the greatest.
- Descending order is the arrangement from the greatest to the smallest.
- The largest 2-digit number is 99. The next number is 100, which is the smallest 3-digit number. In other words, the largest 2-digit number + 1 = smallest 3-digit number. Similarly, the largest 3-digit number is 999, which is followed by 1000, which is the smallest 4-digit number, and so on.
- Commas help in reading large numbers.
- In the Indian system of numeration, the first comma is put after three digits while reading from the right, and then after every second digit from the right. These commas represent thousand, lakhs, crores, etc. For instance, 11,52,794 is words will be eleven lakhs fifty-two thousand seven hundred ninety-four.
- In the International system of numeration, the commas are put after every third digit while reading from the right. These commas represent thousands, millions, billions etc. Therefore, the above number will be written as 1,152,795 or one million one hundred fifty-two thousand seven hundred ninety-five.
- While referring to units of measurement, kilo stands for 1000 times greater, centi stands for 100 times smaller, and milli stands for 1000 times smaller. For example,
- 1 kilometre = 1000 metres
- 1 meter = 100 centimetres
- 1 meter = 1000 millimetres
- Estimation is helpful when we do not need the exact value and just an approximate value is sufficient.
- Depending on the level of accuracy required we can approximate a number to the nearest tens, hundreds, thousands, etc by rounding off. For example, 6744 can be approximated as 6740 if we want to do it to the nearest tens, 6700 if it is t the nearest hundreds or 7000 is it is to the nearest thousands.
- Rounding off helps in estimating a quick solution to an operation like addition, multiplication, etc.
- While carrying out multiple number operations, brackets help in eliminating any confusion.
- We usually use the Hindu-Arabic system of numerals, but the Roman system of numerals is also used for some specific cases.
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