To multiply \(0.2\) by \(2.1\), follow these steps:
1. Set up the multiplication:
[tex]\[
0.2 \times 2.1
\][/tex]
2. Perform the multiplication:
[tex]\[
0.2 \times 2.1 = 0.42000000000000004
\][/tex]
3. Match the result with the given options:
[tex]\[
F \quad 49 \\
H \quad 0.42 \\
Q \quad 4.2 \\
J \quad 0.042
\][/tex]
The detailed calculation reveals that the exact product of multiplying \(0.2\) by \(2.1\) is close to \(0.42\). Thus, the correct answer from the provided options is:
[tex]\[
\boxed{H}
\][/tex]
