Question

Which of the following options shows incorrect subtraction?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Say: Let’s read the question and observe the given options.

Ask:
$\bullet$ Does option A show the correct solution?
Ans: In Option A, 8 is split into $6$ and $2,$ so that we make $16$ a $10$ by subtracting $6$ from $16$ and the remaining $2$ can be subtracted later from $10$ to get $8$ as the difference, i.e., $10–2=8.$ So this is a correct solution.
$\bullet$ Does option B show the correct solution?
Ans: In Option B, $9$ is split into $7$ and $2,$ so that we make $17$ a $10$ by subtracting $7$ from $17$ and the remaining $2$ can be subtracted later from $10$ to get $8$ as the difference, i.e., $10–2=8.$ So this is also a correct solution.
$\bullet$ Does option C show the correct solution?
Ans: In Option C, $8$ is split into $7$ and $1$, so that we make $17$ a $10$ by subtracting $7$ from $17$ and the remaining $1$ can be subtracted later from $10$ to get $9$ as the difference, i,e., $10–1=9.$ So this is also a correct solution.
$\bullet$ Does option D show the correct solution?
Ans: In Option D, $9$ is split into $7$ and $2$, which is incorrect because to make a $10,9$ should be split into $6$ and $3$, so that we make $16$a $10$ by subtracting $6$ from $16$ and the remaining $3$ can be subtracted later from $10$ to get $7$ as the difference, i.e., $10–3=7.$
Hence, Option D shows an incorrect subtraction equation

WB: If required, use the whiteboard to show the solution.

Probing Question:
Q. Which number of the incorrect solution can be changed to make it correct?
A: If the number $16$ can be changed to $17,$ the solution will become correct.