Final answer:
Subtracting 141.7 from 356.4 gives us 214.7, and adding 0.3 to 212.6 gives us 212.9. However, since 214.7 is not equal to 212.9, we conclude there is a discrepancy. The correct answer matching the original equation should be 212.9, option d).
Step-by-step explanation:
To solve the equation 356.4 - 141.7 = 212.6 + 0.3 using properties and mental math, we first subtract 141.7 from 356.4, which gives us 214.7.
Next, we add 0.3 to 212.6, to get 212.9.
However, since we want both sides of the equation to be equal and we got different results, we need to identify any potential errors. We can see that 214.7 is not equal to 212.9.
This suggests there might be a mistake in the original problem or in the calculations we performed.
The correct approach should provide an answer of 212.9, aligning with option d).