1st Class Mathematics Numbers Numbers Up to 100

NUMBERS UP TO 100

SYNOPSIS

• A two-digit number can be written in tens and ones.

e.g., 28 = 2 tens 8 ones

Numbers upto 20:   

• Numbers upto 100:

• 10 is the smallest and 99 is the largest two - digit numbers.
• 100 is the smallest three - digit number.
• Three digit numbers have three places - The ones place, the tens place and the hundreds place. 100 is the smallest three - digit number.

• The number before a given number is got by taking 1 less than the given number, e.g., 5 comes before 6. (5 is 1 less than 6.)
• The number after a given number is got by taking 1 more than the given number, e.g., 49 comes after 48. (49 is 1 more than 48.)
• A number just after a given number and just before another given number is the number between the given numbers, e.g., 12 comes in between 11 and 13.
• A one-digit number is smaller than a two-digit number. e.g., 3 is smaller than 12.
• A two-digit number with smaller digit in the tens place is smaller than the other number, when the digits are different. e.g., 27 is smaller than 34 as 2 is smaller than 3.
• A two-digit number with smaller ones place is smaller when the tens digits are same. e.g., 43 is smaller than 48.
• Numbers can be written in two orders -

(a) The smallest to the biggest. (Ascending order)

(b) The biggest to the smallest. (Descending order)  

• Skip Counting by 2's, 3's, 5's and 10's   

(a) By 2 ‘s : 2, 4, 6, 8, ...                       

(b) By 3 ’s: 3, 6, 9, 12,...

(c) By 5's : 5, 10, 15, 20,...    

(d) By 10's: 10, 20, 30, 40, ...

• The smallest two-digit number is 1 more than the largest one-digit number i.e., 10 is 1 more than 9.
• The smallest three-digit number is 1 more than the largest two-digit number i.e., 100 is 1 more than 99.