Add using the standard algorithm

Detailed Explanation: Add using the standard algorithm

To add multi-digit whole numbers or decimals:

1. Line up the place values. Line up the decimal points, then add trailing zeros if needed.
2. Add from right to left.
3. If a column totals 10 or more, write the ones digit and regroup the tens digit into the next column.
4. Bring the decimal point straight down into the answer.

Example:

The zero in $(26.70)$ keeps the decimal places aligned.

• Hundredths: $(8+0=8)$. Write $8$.
• Tenths: $(5+7=12)$. Write $2$ in the tenths place and regroup $1$ ten to the ones place.
• Ones: $(7+6+1=14)$. Write $4$ and regroup $1$ ten to the tens place.
• Tens: $(4+2+1=7)$. Write $7$.
• Hundreds: Bring down $3$.

The decimal point goes straight down:

So, $(347.58+26.70=\boxed{374.28})$.