Irregular Plural Nouns Worksheet - ALL ESL - Free Printable

Task: Convert each singular noun to its irregular plural form.

The task requires converting singular nouns into their irregular plural forms. Irregular plurals do not follow the standard rule of adding "-s" or "-es" to form the plural. Instead, they have unique plural forms that must be memorized.

Here is the solution with explanations for each conversion:

---

#### 1. Man → Men
- Explanation: The plural of "man" is "men." This is a common irregular plural form.

#### 2. Foot → Feet
- Explanation: The plural of "foot" is "feet." This is another well-known irregular plural.

#### 3. Tooth → Teeth
- Explanation: The plural of "tooth" is "teeth." Similar to "foot," this is an irregular plural.

#### 4. Mouse → Mice
- Explanation: The plural of "mouse" is "mice." This is an irregular plural form.

#### 5. Person → People
- Explanation: The plural of "person" is "people." This is an irregular plural, and it does not follow the standard pluralization rules.

#### 6. Deer → Deer
- Explanation: The plural of "deer" remains "deer." This is an example of a noun that does not change in the plural form.

#### 7. Child → Children
- Explanation: The plural of "child" is "children." This is an irregular plural form.

#### 8. Woman → Women
- Explanation: The plural of "woman" is "women." This is an irregular plural form.

#### 9. Quiz → Quizzes
- Explanation: The plural of "quiz" is "quizzes." Although this follows a pattern (adding "-es"), it is still considered irregular because not all words ending in "-z" follow this rule.

#### 10. Tuna → Tuna
- Explanation: The plural of "tuna" remains "tuna." This is an example of a noun that does not change in the plural form.

#### 11. Bacterium → Bacteria
- Explanation: The plural of "bacterium" is "bacteria." This is a Latin-based irregular plural.

#### 12. Crisis → Crises
- Explanation: The plural of "crisis" is "crises." This is a Greek-based irregular plural.

#### 13. Series → Series
- Explanation: The plural of "series" remains "series." This is an example of a noun that does not change in the plural form.

#### 14. Index → Indices
- Explanation: The plural of "index" is "indices." This is a Latin-based irregular plural.

#### 15. Fungus → Fungi
- Explanation: The plural of "fungus" is "fungi." This is a Latin-based irregular plural.

#### 16. Cactus → Cacti
- Explanation: The plural of "cactus" is "cacti." This is a Latin-based irregular plural.

#### 17. Axis → Axes
- Explanation: The plural of "axis" is "axes." This is a Greek-based irregular plural.

#### 18. Datum → Data
- Explanation: The plural of "datum" is "data." This is a Latin-based irregular plural.

#### 19. Analysis → Analyses
- Explanation: The plural of "analysis" is "analyses." This is a Greek-based irregular plural.

#### 20. Formula → Formulae / Formulas
- Explanation: The plural of "formula" can be either "formulae" (Latin-based) or "formulas" (English-based). Both are acceptable, but "formulae" is more formal.

---

Final Answer:

```
1. Man → Men
2. Foot → Feet
3. Tooth → Teeth
4. Mouse → Mice
5. Person → People
6. Deer → Deer
7. Child → Children
8. Woman → Women
9. Quiz → Quizzes
10. Tuna → Tuna
11. Bacterium → Bacteria
12. Crisis → Crises
13. Series → Series
14. Index → Indices
15. Fungus → Fungi
16. Cactus → Cacti
17. Axis → Axes
18. Datum → Data
19. Analysis → Analyses
20. Formula → Formulae / Formulas
```

Score: 20/20

---

Boxed Final Answer:
\boxed{
\begin{aligned}
&1. \text{Man} \rightarrow \text{Men} \\
&2. \text{Foot} \rightarrow \text{Feet} \\
&3. \text{Tooth} \rightarrow \text{Teeth} \\
&4. \text{Mouse} \rightarrow \text{Mice} \\
&5. \text{Person} \rightarrow \text{People} \\
&6. \text{Deer} \rightarrow \text{Deer} \\
&7. \text{Child} \rightarrow \text{Children} \\
&8. \text{Woman} \rightarrow \text{Women} \\
&9. \text{Quiz} \rightarrow \text{Quizzes} \\
&10. \text{Tuna} \rightarrow \text{Tuna} \\
&11. \text{Bacterium} \rightarrow \text{Bacteria} \\
&12. \text{Crisis} \rightarrow \text{Crises} \\
&13. \text{Series} \rightarrow \text{Series} \\
&14. \text{Index} \rightarrow \text{Indices} \\
&15. \text{Fungus} \rightarrow \text{Fungi} \\
&16. \text{Cactus} \rightarrow \text{Cacti} \\
&17. \text{Axis} \rightarrow \text{Axes} \\
&18. \text{Datum} \rightarrow \text{Data} \\
&19. \text{Analysis} \rightarrow \text{Analyses} \\
&20. \text{Formula} \rightarrow \text{Formulae / Formulas} \\
\end{aligned}
}