Students often refer to Class 5 Maths Notes and Chapter 1 We the Travellers 1 Class 5 Notes during last-minute revisions.
Class 5 Maths Chapter 1 Notes We the Travellers 1
Class 5 Maths Notes Chapter 1 – Class 5 We the Travellers 1 Notes
All numbers are built from just ten basic digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Remember how adding 1 to the biggest 3-digit number (999) gives us 1000, that is, the smallest 4-digit number. We can also make the greatest number by arranging digits from largest to smallest, and the smallest by arranging them from smallest to largest. We also know how to compare larger numbers, looking at their thousands, hundreds, tens, and ones places and figure out which number is bigger or smaller, put them in order, and create new numbers using given digits.
→ The smallest 4-digit number is 1000 and greatest 4-digit number is 9999.
→ If we add 1 to the greatest 4-digit number, we get 9999 + 1 = 10,000, a 5-digit number called ‘Ten Thousand’.
→ The smallest 5-digit number is 10,000 and greatest 5-digit number is 99,999.
→ The expanded form of a number is a way of expressing it as the sum of the place values of all its digits.
→ To round off a number to the nearest 10, look at the digit at the ones place of the given number.
- If the digit is less than 5, replace the digit by 0 and keep the other digits as it is.
- If the digit is 5 or more, add 1 to the digit at the tens place and replace the digit at the ones place with 0, keeping the other digits as it is.
→ To round off a number to the nearest 100, look at the digit at tens place of the given number.
- If the digit is less than 5, replace tens and ones digits by 0 and keep the other digits as it is.
- If digit at the tens place is 5 or more, add 1 to the digit at the hundreds place and replace the digits at the tens and ones place by 0, keeping the other digits as it is.
→ To round off a number to the nearest 1000, look at the digit at the hundreds place of the given number.
- If the digit is less than 5, replace the digits at hundreds, tens and ones place by 0 and keep the other digits as it is.
- If the digit is 5 or more, add 1 to the digit at thousands place, replace each digit on its right by 0 and keep other digits as it is.
Reading And Writing of a Number
→ In Indian place value system, we use ones, tens, hundreds, thousands, ten thousands, etc. from the right side.
→ We use commas after digits from the rightmost side in the pattern: 3,2,2,2, …
→ The place value chart for Indian system is given below
→ Reading numbers means saying the number in words by understanding the place value of each digit. It is also known as Number Name.
e.g. We have, 12305.
In Indian place value system, 12305 is written as 12,305 and read as (i.e. its number name) Twelve Thousand Three Hundred Five.
→ The place value chart for 12,305 is
→ Moreover, we can write it in the following ways as well
12,305 = 10,000 + 2,000 + 300 + 5 or
12,305 = 1 Ten thousand + 2 Thousands + 3 Hundreds + 5 Ones or
12,305 = 12 Thousands + 3 Hundreds + 5 Ones
Comparison of Numbers
→ Comparing numbers means identifying which number is smaller (<), greater (>) or equal (=).
→ A number with more digits is always greater.
e.g. 4,532 > 532
→ If the number of digits is same then we compare from left to right using place value.
e.g. 5,432 and 5,729
→ As first digit (thousands place value) is same, so we compare 4 and 7 (hundreds place value).
Since, 4 < 7
∴ 5,432 < 5,729
→ We can arrange any set of numbers in an increasing (ascending) or (descending) order.
Swapping
→ Swapping means exchanging or interchanging the positions of two digits in a number to create a new number.
e.g. Swapping of 4 and 7 in 1,478 gives 1,748.
→ With the help of swapping or interchanging, we can make a number as large as possible, as small as possible, greater or less than a specific number and lying between two particular number.
Nearest Tens, Hundreds and Thousands
→ The nearest 10 s, 100 s and 1,000 s to a given number refers to the numbers which are the closest multiples of 10 , 100 and 1000 , respectively.
e.g. We have, 3,856.
→ Then, the nearest tens, hundreds and thousands to 3,856 are 3,860,3,900 and 4,000 , respectively.
Methods to find Nearest Value
To determine the nearest 10 s, 100 s and 1,000 s to a given number, first, identify the place which we are rounding and check whether the digit just to the right of that place is less than 5 , equals 5 or greater than 5.
→ If the digit is less than 5 then keep the rounding digit same and change all the digits to the right to 0 .
e.g. The nearest tens, hundreds and thousands to 9,234 are 9,230 (as 4 < 5), 9,200 (as 3 < 5) and 9,000 (as 2 < 5), respectively.
→ If the digit is 5 or more than 5 then increase the rounding digit by 1 and change all the digits to the right to 0.
→ e.g. The nearest tens, hundreds and thousands to 9,876 are 9,880 (as 6 > 5), 9,900 (as 7 > 5) and 10,000 (as 8 > 5), respectively.