You buy a toy. It costs ten dollars. That is the expense.
Today we learn four words. “Expense,” “expensive,” “expensively,” and “inexpensive.”
Each word shares the idea of cost. Each does a different job.
Parents and children can learn these words together. They help with budgets.
What Does “Same Word, Different Forms” Mean?
One idea takes different shapes. The idea here is the price of something.
“Expense” is a noun. “The expense of the trip was high.” Cost.
“Expensive” is an adjective. “A diamond is expensive.” Describes.
“Expensively” is an adverb. “She dressed expensively.” Describes a verb.
“Inexpensive” is an adjective. “A pencil is inexpensive.” Low cost.
Same root. Different endings. Different jobs. The cost stays.
Personal Pronouns Change Their Form
Pronouns change for grammar. “I” becomes “me.” “We” becomes “us.”
Our words change for role and description. “The expense was too high.” Noun.
“This coat is expensive.” Describes. “He lives expensively.” How.
“That shirt is inexpensive.” Opposite.
Pronouns help us speak faster. Word families help us talk about money.
When children know these four words, they compare prices.
From Verb to Noun to Adjective to Adverb – One Family, Many Words
“Expense” is a noun. “Food is a monthly expense.” Cost.
“Expensive” is an adjective. “An expensive car costs a lot.” Describes.
“Expensively” is an adverb. “The hotel was expensively decorated.” Describes.
“Inexpensive” is an adjective. “An inexpensive gift can still be thoughtful.” Low price.
We have no verb in this family.
Four members. Essential for shopping.
One Root, Many Roles – How Words Grow from Actions to Qualities
The root “expense” comes from Latin “expendere,” meaning to weigh out money. “Ex-” out + “pendere” to weigh.
From that root, we add “-ive” to make an adjective. “Expensive” means costing a lot.
We add “-ly” to make an adverb. “Expensively” means in an expensive way.
We add “in-” as a prefix to make the opposite. “Inexpensive” means not expensive.
Help your child see this pattern. Expense is the cost. Expensive describes high cost. Expensively tells how. Inexpensive describes low cost.
Same Meaning, Different Jobs – Is It a Verb or a Noun?
Look at “expense.” Always a noun. “Vacation expenses add up.”
“Expensive” is always an adjective. “This restaurant is expensive.”
“Expensively” is always an adverb. “The restaurant was expensively decorated.”
“Inexpensive” is always an adjective. “The meal was inexpensive.”
No word plays two jobs. Each has one clear role.
Teach children that “inexpensive” is a polite way to say “cheap.”
Adjectives and Adverbs – When Do We Add -ly?
We add “-ly” to “expensive” to make “expensively.” This is the rule.
Adjective + ly = adverb. “Expensive” + “ly” = “expensively.”
Example: “The watch is expensive.” Adjective. “It is expensively made.” Adverb.
We do not add “-ly” to “expense” or “inexpensive.”
For children, “expensively” is useful but less common. Focus on “expensive” and “inexpensive.”
Watch Out for Tricky Spelling Changes (Double Letters, y to i, and More)
Spelling here is very regular. No double letters. No y to i changes.
“Expense” adds “-ive” to make “expensive.” Keep the “s.” Expens + ive = expensive.
“Expensive” adds “-ly” to make “expensively.” Keep all letters. Expensive + ly = expensively.
“In-” adds to “expensive” to make “inexpensive.” In + expensive = inexpensive.
No dropping. No vowel changes. Very clean.
Practice with your child. Write “expense.” Add “ive.” You get “expensive.” Add “ly.” You get “expensively.” Put “in” in front of “expensive.” You get “inexpensive.”
Let’s Practice – Can You Choose the Right Form?
Try these sentences. Fill in the blank with expense, expensive, expensively, or inexpensive.
The _____ of a new phone is high. (noun)
This jacket is too _____. I cannot afford it. (adjective)
The mansion was _____ furnished. (adverb)
A plastic fork is _____. (adjective, low cost)
We need to track our monthly _____. (noun)
That restaurant is _____, but the food is delicious. (adjective)
She dresses _____ even for casual days. (adverb)
An _____ option is to bring your own lunch. (adjective)
Answers: 1 expense, 2 expensive, 3 expensively, 4 inexpensive, 5 expenses, 6 expensive, 7 expensively, 8 inexpensive.
Number 5 uses the plural “expenses.” Our keyword is “expense.” Acceptable.
Number 8 uses “inexpensive” as an adjective.
Tips for Parents – Help Your Child Learn Word Families in a Fun Way
Talk about the expense of items. “The expense of a video game is fifty dollars.”
Call expensive things high cost. “That robot toy is expensive.”
Use expensively for special things. “This cake was expensively decorated.”
Point to inexpensive options. “A pencil is inexpensive.”
Play a game. You name an object. Your child says “expensive” or “inexpensive.”
“A diamond ring.” “Expensive.” “A rubber band.” “Inexpensive.”
Draw a price tag. Write “expensive” on one and “inexpensive” on another.
Read a book about money. “Alexander, Who Used to Be Rich Last Sunday” by Judith Viorst.
Do not correct every mistake. If your child says “expense” for “expensive,” gently say “The expense is the cost. The item is expensive.”
Celebrate when your child uses “inexpensive.” That word is great for smart shopping.
Explain that “expensive” means costing much money. “Inexpensive” means costing little.
Tomorrow you will see the expense of a movie ticket. You will choose not to buy an expensive toy. You will not dress expensively for school. You will pick an inexpensive snack.
Your child might say “Love is not expensive. It is free.” You will hug them.
Keep tracking expenses. Keep noticing expensive things. Keep spending wisely, not expensively. Keep finding inexpensive joys.
Your child will grow in language and in financial sense. Cost matters. Words help us weigh it.
