Question

adding decimals worksheet
94.6
+ 36.8

35.75
+ 387.8

88.55
+ 25.8

731.89
+ 462.9

1308.8
+ 6387.1

128.2
+ 399.8

63.88
+ 82.17

3029.2
+ 5527.7

119.8
+ 487.1

362.6
431.2
+ 298.5

80.82
62.17
+ 13.99

263.9
581.7
+ 198.7

Answer:

To solve these decimal addition problems, we follow the standard procedure of aligning the decimal points and adding the numbers column by column, carrying over when necessary. Let's solve each problem step by step:

1. \(

$$\begin{array}{r} 94.6 \\ +\ 36.8 \\ \hline \end{array}$$

\)

Step 1: Align decimals and add tenths place:

\( 0.6 + 0.8 = 1.4 \). Write down \( 0.4 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 4 + 6 + 1 = 11 \). Write down \( 1 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 9 + 3 + 1 = 13 \).

Step 4: Combine results:

\( 131.4 \)

2. \(

$$\begin{array}{r} 35.75 \\ +\ 387.8 \\ \hline \end{array}$$

\)

Step 1: Align decimals (note \( 387.8 = 387.80 \)):

\( 0.75 + 0.80 = 1.55 \). Write down \( 0.55 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 5 + 7 + 1 = 13 \). Write down \( 3 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 3 + 8 + 1 = 12 \). Write down \( 2 \) and carry over \( 1 \).

Step 4: Add hundreds place with carry:

\( 0 + 3 + 1 = 4 \).

Step 5: Combine results:

\( 423.55 \)

3. \(

$$\begin{array}{r} 88.55 \\ +\ 25.8 \\ \hline \end{array}$$

\)

Step 1: Align decimals (note \( 25.8 = 25.80 \)):

\( 0.55 + 0.80 = 1.35 \). Write down \( 0.35 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 8 + 5 + 1 = 14 \). Write down \( 4 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 8 + 2 + 1 = 11 \).

Step 4: Combine results:

\( 114.35 \)

4. \(

$$\begin{array}{r} 731.89 \\ +\ 462.9 \\ \hline \end{array}$$

\)

Step 1: Align decimals (note \( 462.9 = 462.90 \)):

\( 0.89 + 0.90 = 1.79 \). Write down \( 0.79 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 1 + 2 + 1 = 4 \).

Step 3: Add tens place:

\( 3 + 6 = 9 \).

Step 4: Add hundreds place:

\( 7 + 4 = 11 \).

Step 5: Combine results:

\( 1194.79 \)

5. \(

$$\begin{array}{r} 1308.8 \\ +\ 6387.1 \\ \hline \end{array}$$

\)

Step 1: Align decimals:

\( 0.8 + 0.1 = 0.9 \).

Step 2: Add ones place:

\( 8 + 7 = 15 \). Write down \( 5 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 0 + 8 + 1 = 9 \).

Step 4: Add hundreds place:

\( 3 + 3 = 6 \).

Step 5: Add thousands place:

\( 1 + 6 = 7 \).

Step 6: Combine results:

\( 7695.9 \)

6. \(

$$\begin{array}{r} 128.2 \\ +\ 399.8 \\ \hline \end{array}$$

\)

Step 1: Align decimals:

\( 0.2 + 0.8 = 1.0 \). Write down \( 0.0 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 8 + 9 + 1 = 18 \). Write down \( 8 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 2 + 9 + 1 = 12 \). Write down \( 2 \) and carry over \( 1 \).

Step 4: Add hundreds place with carry:

\( 1 + 3 + 1 = 5 \).

Step 5: Combine results:

\( 528.0 \) (or \( 528 \))

7. \(

$$\begin{array}{r} 63.88 \\ +\ 82.17 \\ \hline \end{array}$$

\)

Step 1: Add hundredths place:

\( 0.08 + 0.07 = 0.15 \). Write down \( 0.05 \) and carry over \( 1 \).

Step 2: Add tenths place with carry:

\( 0.8 + 0.1 + 1 = 1.0 \). Write down \( 0.0 \) and carry over \( 1 \).

Step 3: Add ones place with carry:

\( 3 + 2 + 1 = 6 \).

Step 4: Add tens place:

\( 6 + 8 = 14 \).

Step 5: Combine results:

\( 146.05 \)

8. \(

$$\begin{array}{r} 3029.2 \\ +\ 5527.7 \\ \hline \end{array}$$

\)

Step 1: Align decimals:

\( 0.2 + 0.7 = 0.9 \).

Step 2: Add ones place:

\( 9 + 7 = 16 \). Write down \( 6 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 2 + 2 + 1 = 5 \).

Step 4: Add hundreds place:

\( 0 + 5 = 5 \).

Step 5: Add thousands place:

\( 3 + 5 = 8 \).

Step 6: Combine results:

\( 8556.9 \)

9. \(

$$\begin{array}{r} 119.8 \\ +\ 487.1 \\ \hline \end{array}$$

\)

Step 1: Align decimals:

\( 0.8 + 0.1 = 0.9 \).

Step 2: Add ones place:

\( 9 + 7 = 16 \). Write down \( 6 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 1 + 8 + 1 = 10 \). Write down \( 0 \) and carry over \( 1 \).

Step 4: Add hundreds place with carry:

\( 1 + 4 + 1 = 6 \).

Step 5: Combine results:

\( 606.9 \)

10. \(

$$\begin{array}{r} 362.6 \\ 431.2 \\ +\ 298.5 \\ \hline \end{array}$$

\)

Step 1: Add tenths place:

\( 0.6 + 0.2 + 0.5 = 1.3 \). Write down \( 0.3 \) and carry over \( 1 \).

Step 2: Add ones place with carry:

\( 2 + 1 + 8 + 1 = 12 \). Write down \( 2 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 6 + 3 + 9 + 1 = 19 \). Write down \( 9 \) and carry over \( 1 \).

Step 4: Add hundreds place with carry:

\( 3 + 4 + 2 + 1 = 10 \). Write down \( 0 \) and carry over \( 1 \).

Step 5: Add thousands place with carry:

\( 0 + 0 + 0 + 1 = 1 \).

Step 6: Combine results:

\( 1092.3 \)

11. \(

$$\begin{array}{r} 80.82 \\ 62.17 \\ +\ 13.99 \\ \hline \end{array}$$

\)

Step 1: Add hundredths place:

\( 0.02 + 0.07 + 0.09 = 0.18 \). Write down \( 0.08 \) and carry over \( 1 \).

Step 2: Add tenths place with carry:

\( 0.8 + 0.1 + 0.9 + 1 = 1.9 \). Write down \( 0.9 \) and carry over \( 1 \).

Step 3: Add ones place with carry:

\( 0 + 2 + 3 + 1 = 6 \).

Step 4: Add tens place:

\( 8 + 6 + 1 = 15 \).

Step 5: Combine results:

\( 156.98 \)

12. \(

$$\begin{array}{r} 263.9 \\ 581.7 \\ +\ 198.7 \\ \hline \end{array}$$

\)

Step 1: Add tenths place:

\( 0.9 + 0.7 + 0.7 = 2.3 \). Write down \( 0.3 \) and carry over \( 2 \).

Step 2: Add ones place with carry:

\( 3 + 1 + 8 + 2 = 14 \). Write down \( 4 \) and carry over \( 1 \).

Step 3: Add tens place with carry:

\( 6 + 8 + 9 + 1 = 24 \). Write down \( 4 \) and carry over \( 2 \).

Step 4: Add hundreds place with carry:

\( 2 + 5 + 1 + 2 = 10 \). Write down \( 0 \) and carry over \( 1 \).

Step 5: Add thousands place with carry:

\( 0 + 0 + 0 + 1 = 1 \).

Step 6: Combine results:

\( 1044.3 \)

Final Answers:

1. \( \boldsymbol{131.4} \)
2. \( \boldsymbol{423.55} \)
3. \( \boldsymbol{114.35} \)
4. \( \boldsymbol{1194.79} \)
5. \( \boldsymbol{7695.9} \)
6. \( \boldsymbol{528} \) (or \( 528.0 \))
7. \( \boldsymbol{146.05} \)
8. \( \boldsymbol{8556.9} \)
9. \( \boldsymbol{606.9} \)
10. \( \boldsymbol{1092.3} \)
11. \( \boldsymbol{156.98} \)
12. \( \boldsymbol{1044.3} \)