Question

Which number should replace the ç to make the subtraction problem correct?

9.866
- 7.97ç
1.889
3
6
7
8

Answer 1

To find the number that should replace ç in the subtraction problem, we can set up the equation based on the subtraction provided:

\[
9.866 - 7.97ç = 1.889
\]

First, we can add 7.97ç to both sides:

\[
9.866 = 1.889 + 7.97ç
\]

Next, we subtract 1.889 from both sides to isolate the term with ç:

\[
9.866 - 1.889 = 7.97ç
\]

Calculating the left side:

\[
9.866 - 1.889 = 7.977
\]

Now we have:

\[
7.977 = 7.97ç
\]

To find ç, we divide both sides by 7.97:

\[
ç = \frac{7.977}{7.97}
\]

Calculating the value:

\[
ç \approx 1.00125
\]

Since ç needs to be a single digit and can only be 3, 6, 7, or 8, let's check these values one by one. We will substitute possible values for ç into \(7.97ç\) and check whether the subtraction equals 1.889.

1. If ç = 3:
\[
7.973 = 7.973 \Rightarrow 9.866 - 7.973 = 1.893 \quad (\text{Not correct})
\]

2. If ç = 6:
\[
7.976 = 7.976 \Rightarrow 9.866 - 7.976 = 1.890 \quad (\text{Not correct})
\]

3. If ç = 7:
\[
7.977 = 7.977 \Rightarrow 9.866 - 7.977 = 1.889 \quad (\text{Correct})
\]

4. If ç = 8:
\[
7.978 = 7.978 \Rightarrow 9.866 - 7.978 = 1.888 \quad (\text{Not correct})
\]

The only value that results in a correct subtraction of 1.889 is ç = 7.

Therefore, the number that should replace ç is **7**.