The Noun: Numbers

Nouns have two numbers: The Singular number and the Plural number.
The word - number - refers to whether a noun is only one or more than one. 

Singular Number 
A noun is said to be in the singular number when it is used to mean one person or thing:- baby, toy, life, child, man, girl, doll, bus, mango etc.
Plural Number 
A noun is said to be in the plural number when it is used to mean more than one person or thing:- babies, toys, lives, children, men, girls, dolls, buses, mangoes, etc.

(i) Countable Nouns

• ​Countable Nouns are the things we can count; as, pens, books, bags, chairs, tables, apples, benches, etc. 
• A singular countable noun always takes a or an before it. 
• We can use a countable noun in the singular and also in the plural; as, This is a pen. These are pens. That is an apple. Those are apples.

(ii) Uncountable Nouns

• ​Uncountable Nouns are the things we cannot count; as, butter, ghee, honey, tea, wool, air, water, milk, oil etc. 
• We never use a or an before an uncountable noun and we don't use an uncountable noun in the plural; as, we can say two pens but we can't say two water.
• We can use some with an uncountable noun. We can use some with a countable noun in the plural; as, Please give me some biscuits. Please give me some milk.

Rules for the Change of Numbers

• By adding the letter 's' to the noun in singular; 
  apple - apples, 
  bag - bags, 
  cat - cats, etc.
• Nouns ending in s, ss, sh, ch, x or z form their plurals by adding - 'es' to the singular; 
  bush - bushes, 
  bus - buses, 
  glass - glasses, etc.
• If a Singular Noun ends in y with a vowel before it, the plural is formed by adding s only; 
  Boy - Boys, 
  Bay - Bays, 
  Chimney - Chimneys, 
  Donkey - Donkeys, etc.
• If the Singular Noun ends in f or fe the plural is formed by changing f or fe into v and then adding es; 
  Calf - Calves, 
  Elf - Elves, 
  Half - Halves, 
  Knife - Knives, etc.

Rules for Making Plural Nouns
Consider the following rules while making a singular noun to plural.

• If a Singular Noun ends in y and there is a consonant before y the plural is formed by changing y into i and adding es; 
  Army - Armies, 
  Assembly - Assemblies, 
  Baby - Babies, etc.
• Similarly,  we can change the following: Country, city, cry, copy, dairy, diary, duty, enemy, fairy, fly, fury, gallery, gully, history, hobby, lady, lorry, lilly, luxury, penny, pony, policy, sky, story, victory.
• If the Singular Noun ends in ief, ff, ef, or f then the plural is formed by adding s to them; 
  Belief - Beliefs, 
  Chief - Chiefs, 
  Cliff - Cliffs, 
  Dwarf - Dwarfs, etc.
• Similarly, we can do for the following: Handkerchief, hoof, mischief, gulf, grief, proof, roof, safe, serf, staff, strife, brief, etc.
  

1. Irregular Plural

• The nouns which do not form their plurals by adding s or es are called irregular plurals.

2. Plural of Compound Nouns

• If the Compound Noun is made of two nouns, the second noun is changed into the Plural Form; 
  Foot-man: Foot-men, 
  Governor-General: Governor- Generals, 
  Step-son: Step-sons, 
  Step-daughter: Step-daughters, 
  Gentle-man: Gentle-men, 
  Maid-Servant: Maid Servants, etc.