Find the step between consecutive terms. The sequence is decreasing.<br><br>
&bull; From 20.4 to 19.2, there are 2 steps: 20.4 − 19.2 = 1.2, so each step = 1.2 ÷ 2 = 0.6.<br>
&bull; First blank: 20.4 − 0.6 = 19.8<br>
&bull; Second blank: 18.6 − 0.6 = 18.0<br>
&bull; Verify: 18.0 − 0.6 = 17.4 (matches the last term).<br>
&bull; Sequence: 20.4, 19.8, 19.2, 18.6, 18.0, 17.4<br><br>
Final Answer: 19.8, 18.0