Question

or subtract.
1 ( 2 + 9 = ) ____
2 ( 5 + 7 = ) ____
3 ( 8 + 3 = ) ____
4 ( 10 - 1 = ) ____
5 ( 11 - 4 = ) ____
6 ( 12 - 6 = ) ____
7 ( 7 + 5 = ) ____
8 ( 8 + 2 = ) ____
9 ( 4 + 7 = ) ____
10 ( 10 - 5 = ) ____
11 ( 12 - 9 = ) ____
12 ( 6 + 5 = ) ____
13 ( \begin{align} & 9\\ & +1\\ hline end{align} ) ( \begin{align} & 4\\ & +8\\ hline end{align} ) ( \begin{align} & 11\\ & -9\\ hline end{align} ) ( \begin{align} & 3\\ & +8\\ hline end{align} )
14 ( \begin{align} & 6\\ & +4\\ hline end{align} ) ( \begin{align} & 12\\ & -7\\ hline end{align} ) ( \begin{align} & 11\\ & -5\\ hline end{align} ) ( \begin{align} & 12\\ & -8\\ hline end{align} )
15 ( \begin{align} & 12\\ & -3\\ hline end{align} ) ( \begin{align} & 3\\ & +7\\ hline end{align} ) ( \begin{align} & 9\\ & +3\\ hline end{align} ) ( \begin{align} & 5\\ & +5\\ hline end{align} )
16 ( \begin{align} & 8\\ & +4\\ hline end{align} ) ( \begin{align} & 10\\ & -6\\ hline end{align} ) ( \begin{align} & 12\\ & -5\\ hline end{align} ) ( \begin{align} & 11\\ & -3\\ hline end{align} )
17 ( \begin{align} & 10\\ & -8\\ hline end{align} ) ( \begin{align} & 3\\ & +9\\ hline end{align} ) ( \begin{align} & 11\\ & -7\\ hline end{align} ) ( \begin{align} & 6\\ & +6\\ hline end{align} )
now try this!
write the correct sign.
1 ( \begin{align} & 8\\ & 3\\ & 5\\ hline end{align} ) (with a circle between 8 and 3/5)
2 ( \begin{align} & 12\\ & 7\\ & 5\\ hline end{align} ) (with a circle between 12 and 7/5)
3 ( \begin{align} & 4\\ & 5\\ & 9\\ hline end{align} ) (with a circle between 4 and 5/9)
4 ( \begin{align} & 6\\ & 6\\ & 0\\ hline end{align} ) (with a circle between 6 and 6/0)
5 ( \begin{align} & 7\\ & 4\\ & 11\\ hline end{align} ) (with a circle between 7 and 4/11)

Explanation:

Step1: Calculate each arithmetic expression

• \(2 + 9=11\)
• \(5 + 7 = 12\)
• \(8+3 = 11\)
• \(10 - 1=9\)
• \(11-4 = 7\)
• \(12-6 = 6\)
• \(7 + 5=12\)
• \(8+2 = 10\)
• \(4+7 = 11\)
• \(10-5 = 5\)
• \(12-9 = 3\)
• \(6 + 5=11\)
• \(

$$\begin{array}{r}9\\+1\\\hline10\end{array}$$

\)

• \(

$$\begin{array}{r}4\\+8\\\hline12\end{array}$$

\)

• \(

$$\begin{array}{r}11\\-9\\\hline2\end{array}$$

\)

• \(

$$\begin{array}{r}3\\+8\\\hline11\end{array}$$

\)

• \(

$$\begin{array}{r}6\\+4\\\hline10\end{array}$$

\)

• \(

$$\begin{array}{r}12\\-7\\\hline5\end{array}$$

\)

• \(

$$\begin{array}{r}11\\-5\\\hline6\end{array}$$

\)

• \(

$$\begin{array}{r}12\\-8\\\hline4\end{array}$$

\)

• \(

$$\begin{array}{r}12\\-3\\\hline9\end{array}$$

\)

• \(

$$\begin{array}{r}3\\+7\\\hline10\end{array}$$

\)

• \(

$$\begin{array}{r}9\\+3\\\hline12\end{array}$$

\)

• \(

$$\begin{array}{r}5\\+5\\\hline10\end{array}$$

\)

• \(

$$\begin{array}{r}8\\+4\\\hline12\end{array}$$

\)

• \(

$$\begin{array}{r}10\\-6\\\hline4\end{array}$$

\)

• \(

$$\begin{array}{r}12\\-5\\\hline7\end{array}$$

\)

• \(

$$\begin{array}{r}11\\-3\\\hline8\end{array}$$

\)

• \(

$$\begin{array}{r}10\\-8\\\hline2\end{array}$$

\)

• \(

$$\begin{array}{r}3\\+9\\\hline12\end{array}$$

\)

• \(

$$\begin{array}{r}11\\-7\\\hline4\end{array}$$

\)

• \(

$$\begin{array}{r}6\\+6\\\hline12\end{array}$$

\)

Step2: Determine the operation signs

• For \(8\) and \(3\) with result \(5\), since \(8-3 = 5\), the sign is \(-\)
• For \(12\) and \(7\) with result \(5\), since \(12 - 7=5\), the sign is \(-\)
• For \(4\) and \(5\) with result \(9\), since \(4+5 = 9\), the sign is \(+\)
• For \(6\) and \(6\) with result \(0\), since \(6-6 = 0\), the sign is \(-\)
• For \(7\) and \(4\) with result \(11\), since \(7 + 4=11\), the sign is \(+\)

Answer:

1. \(11\)
2. \(12\)
3. \(11\)
4. \(9\)
5. \(7\)
6. \(6\)
7. \(12\)
8. \(10\)
9. \(11\)
10. \(5\)
11. \(3\)
12. \(11\)
13. \(10\), \(12\), \(2\), \(11\)
14. \(10\), \(5\), \(6\), \(4\)
15. \(9\), \(10\), \(12\), \(10\)
16. \(12\), \(4\), \(7\), \(8\)
17. \(2\), \(12\), \(4\), \(12\)

Operation signs:

1. \(-\)
2. \(-\)
3. \(+\)
4. \(-\)
5. \(+\)