Unit conversion insight: What decimal fraction of one litre is 40 ml?

Introduction / Context:
Fluid measure conversions are routine in science and daily life. Here we express a small volume as a decimal fraction of a standard litre.

Given Data / Assumptions:

• 1 litre = 1000 millilitres.
• We have 40 millilitres.
• Ask for decimal fraction of a litre represented by 40 millilitres.

Concept / Approach:
A decimal fraction of a whole equals part divided by whole. Convert both amounts to consistent units and divide.

Step-by-Step Solution:

Verification / Alternative check:
As a percentage, 0.04 equals 4%. Four percent of a litre is 40 ml, which matches the given amount.

Why Other Options Are Wrong:
0.4 equals 400 ml which is too large. 0.05 equals 50 ml. None of these is invalid because 0.04 appears. 0.4% would be 4 ml not 40 ml.

Common Pitfalls:
Confusing millilitres and litres or dropping a zero when dividing by 1000, which shifts the decimal point incorrectly.

Final Answer:
0.04