1. The problem is to understand how to add decimal values. 2. When adding decimals, align the decimal points vertically to ensure digits of the same place value are added together. 3. Use the addition rule: add digits column by column from right to left, carrying over if the sum exceeds 9. 4. Example: Add $3.75 + 2.4$. 5. Align decimals: \begin{array}{r} 3.75 \\ +2.40 \\ \hline \end{array} 6. Add hundredths place: $5 + 0 = 5$. 7. Add tenths place: $7 + 4 = 11$, write $1$ and carry over $1$ to the units place. 8. Add units place: $3 + 2 + 1 = 6$. 9. Final sum is $6.15$. 10. So, $3.75 + 2.4 = 6.15$. This method works for any decimal addition by aligning decimal points and adding digit by digit.