Answer :
We start with the expression
$$
38.4 + 1.3.
$$
Step 1: Write each number in terms of its whole number and decimal parts. We have:
$$
38.4 = 38 + 0.4 \quad \text{and} \quad 1.3 = 1 + 0.3.
$$
Step 2: Add the whole number parts and the decimal parts separately:
$$
38 + 1 = 39,
$$
$$
0.4 + 0.3 = 0.7.
$$
Step 3: Combine these sums to get the final result:
$$
39 + 0.7 = 39.699999999999996.
$$
Thus, the sum of $38.4$ and $1.3$ is
$$
\boxed{39.699999999999996}.
$$
(Note: The result appears as $39.699999999999996$ due to the way computers represent decimal numbers in floating-point arithmetic.)
$$
38.4 + 1.3.
$$
Step 1: Write each number in terms of its whole number and decimal parts. We have:
$$
38.4 = 38 + 0.4 \quad \text{and} \quad 1.3 = 1 + 0.3.
$$
Step 2: Add the whole number parts and the decimal parts separately:
$$
38 + 1 = 39,
$$
$$
0.4 + 0.3 = 0.7.
$$
Step 3: Combine these sums to get the final result:
$$
39 + 0.7 = 39.699999999999996.
$$
Thus, the sum of $38.4$ and $1.3$ is
$$
\boxed{39.699999999999996}.
$$
(Note: The result appears as $39.699999999999996$ due to the way computers represent decimal numbers in floating-point arithmetic.)
