To find the Consumer Price Index (CPI) from a year ago, we can use the formula that relates the current CPI, the inflation rate, and the CPI from a year ago:

$\text{CPI}_{\text{previous}} = \frac{\text{CPI}_{\text{current}}}{1 + \frac{\text{inflation rate}}{100}}$

Given:

• $\text{CPI}_{\text{current}} = 266.8$
• $\text{inflation rate} = 4.7\%$

Now, we can plug in the values:

$\text{CPI}_{\text{previous}} = \frac{266.8}{1 + \frac{4.7}{100}}$

$\text{CPI}_{\text{previous}} = \frac{266.8}{1.047}$

$\text{CPI}_{\text{previous}} \approx 254.8$

Thus, the CPI a year ago was approximately 254.8.

Would you like more details or have any questions?

Here are five related questions:

1. How would the calculation change if the inflation rate was negative?
2. What does a rising CPI indicate about the economy?
3. How is the CPI used to measure cost-of-living adjustments?
4. What are some limitations of using the CPI as a measure of inflation?
5. How do different countries calculate their version of the CPI?

Tip: When calculating past values given a percentage change, remember to adjust for the change's direction (increase or decrease) in the formula.