Solve Decimal Addition: 0.7 + 0.8 Using Base-10 Blocks

To solve the problem, let's add the decimals 0.7 and 0.8:

• Step 1: Align the numbers by their decimal points:
• $0.7$
• $+0.8$
• Step 2: Add the digits from right to left:
• Tenths place: $7 + 8 = 15$

The result of $7 + 8$ gives $15$. Since we are in the tenths column, the value is 1.5 (carrying the 1 over to the units place). Thus, the sum is $1.5$.

Therefore, the solution to the problem is $\boxed{1.5}$.