Convert Mixed Number 1 4/10 to a Fraction

To solve this problem, we will convert the mixed number $1 \frac{4}{10}$ into a decimal form by following these steps:

• Step 1: Convert the fractional part $\frac{4}{10}$ to a decimal.
  Since the fraction $\frac{4}{10}$ has a denominator of 10, it directly converts to 0.4. This is because dividing 4 by 10 gives us 0.4.
• Step 2: Add this decimal to the whole number part.
  Combine the whole number part (1) with the decimal 0.4 to get the complete number in decimal form:
$1 + 0.4 = 1.4$

Thus, the mixed number $1 \frac{4}{10}$ converted into a decimal is $\mathbf{1.4}$.

The correct choice among the given options is the choice that reads 1.4 (Choice 3).