Decimals and fractions are the same amounts wearing different outfits — 0.75 and 3/4 are one quantity with two names. Converting between them is a two-step trick built entirely on place value, and once your kid sees it, the mystery evaporates. Converter first, then the trick itself.
The converter
The two-step trick (this is the whole lesson)
Example: 0.75
Step 1 — Read the place value, write the fraction. Two decimal digits means hundredths: 0.75 = 75/100. (One digit → tenths, two → hundredths, three → thousandths. The digits literally tell you the denominator.)
Step 2 — Simplify. 75 and 100 both divide by 25: 75/100 = 3/4. Done.
That's genuinely the entire skill: say it correctly, write what you said, simplify. A kid who reads 0.75 aloud as "seventy-five hundredths" (not "point seven five") has already done step 1 with their mouth — which is why the reading habit matters more than any worksheet.
Whole numbers along for the ride
Example: 2.5
The whole number just waits outside: 2.5 = 2 and 5/10 = 2 1/2. (Need an improper fraction instead? 25/10 = 5/2 — same amount, different outfit again.)
The conversions worth just knowing
These come up so often — money, measuring cups, test answers — that recognizing them on sight beats re-deriving them:
| Decimal | Fraction | Kitchen anchor |
|---|---|---|
| 0.5 | 1/2 | half a dollar, half a cup |
| 0.25 | 1/4 | a quarter — the coin IS the lesson |
| 0.75 | 3/4 | three quarters |
| 0.2 | 1/5 | two dimes |
| 0.1 | 1/10 | one dime |
| 0.125 | 1/8 | the half of a quarter cup |
| 0.333… | 1/3 | the famous repeater |
| 0.666… | 2/3 | its big sibling |
About those repeaters: 0.333… really does equal exactly 1/3 (the dots mean the 3s never stop). Converting repeating decimals properly takes algebra, so at elementary level, memorizing the two famous ones is the honest play.
The two mistakes to watch for
- Ignoring place value: turning 0.75 into 7/5 or 0.5 into 5/1 — the digits got copied but the decimal's meaning got dropped. Cure: the say-it-aloud habit. "Seventy-five hundredths" makes 75/100 unavoidable.
- The trailing-zero trap: kids see 0.50 and write 50/100, then panic that it "doesn't match" 0.5 = 5/10. Both simplify to 1/2 — a perfect live demo of equivalent fractions if you catch it happening.
How to practice without tears
Money is the ready-made curriculum: every price tag is a decimal, every coin is a fraction of a dollar. "The gum costs $0.75 — what fraction of a dollar is that? Which coins prove it?" Receipts, gas station signs ($3.49⁹ is a whole conversation), and measuring cups (0.25 cup = the ¼ scoop) turn errands into fluency. Ten minutes of that beats any drill sheet — and it wires together the whole system your kid has been building: place value, simplifying, and equivalents, all shaking hands.
Frequently asked questions
How do you convert a decimal to a fraction?
Read the place value, write it over 10/100/1000, simplify: 0.75 = 75/100 = 3/4.
What is 0.75 as a fraction?
75/100, which simplifies to 3/4.
How do you convert decimals bigger than 1?
The whole number waits outside: 2.5 = 2 and 5/10 = 2 1/2 (or 5/2 improper).
What about repeating decimals like 0.333…?
They have exact fraction forms (0.333… = 1/3 exactly); converting them takes algebra, so elementary kids memorize the common ones.
What grade is this taught?
Tenths/hundredths connections begin in 4th grade; fluency is expected by 5th–6th.
Decimals and fractions, but make them a quest
MathKnights turns conversions - and every other elementary skill - into a knights-and-quests game kids ask to play. Built by a parent, for grades 1-5. Free to start.
Begin the quest - freeThis guide reflects one family's teaching experience plus common U.S. grade-level standards as of July 2026. Every child learns differently.