Question

line up the decimals in vertical form and subtract.

1. 3.6 - 0.8
2. 83.2 - 42.9
3. 67.1 - 9.3
4. 24.3 - 1.5
5. 39.6 - 5.4
6. 91.7 - 40.8
7. 78.3 - 6.4
8. 5.5 - 0.3
9. 16.4 - 3.5
10. 47.5 - 8.2
11. 6.7 - 2.1
12. 81.6 - 54.

Explanation:

1) \( 3.6 - 0.8 \)

Step1: Line up decimals vertically

$$\begin{array}{r} 3.6 \\ - 0.8 \\ \hline \end{array}$$

Step2: Subtract tenths place (borrow if needed)

6 - 8 is not possible, so borrow 1 from the ones place (3 becomes 2, 6 becomes 16). Then \( 16 - 8 = 8 \) in tenths place. Ones place: \( 2 - 0 = 2 \).

$$\begin{array}{r} \overset{2}{3}.\overset{16}{6} \\ - \ \ 0.8 \\ \hline 2.8 \\ \end{array}$$

Step1: Line up decimals vertically

$$\begin{array}{r} 83.2 \\ - 42.9 \\ \hline \end{array}$$

Step2: Subtract tenths place (borrow)

2 - 9 is not possible, borrow 1 from the ones place (3 becomes 2, 2 becomes 12). \( 12 - 9 = 3 \) (tenths). Ones place: \( 2 - 2 = 0 \). Tens place: \( 8 - 4 = 4 \).

$$\begin{array}{r} 8\overset{2}{3}.\overset{12}{2} \\ - 42.9 \\ \hline 40.3 \\ \end{array}$$

Step1: Line up decimals vertically

$$\begin{array}{r} 67.1 \\ - \ \ 9.3 \\ \hline \end{array}$$

Step2: Subtract tenths place (borrow)

1 - 3 is not possible, borrow 1 from the ones place (7 becomes 6, 1 becomes 11). \( 11 - 3 = 8 \) (tenths). Ones place: \( 6 - 9 \) not possible, borrow 1 from tens place (6 becomes 5, 6 becomes 16). \( 16 - 9 = 7 \) (ones). Tens place: \( 5 - 0 = 5 \).

$$\begin{array}{r} \overset{5}{6}\overset{16}{7}.\overset{11}{1} \\ - \ \ \ 9.3 \\ \hline 57.8 \\ \end{array}$$

Answer:

\( 2.8 \)

2) \( 83.2 - 42.9 \)