Question

There are $16$ big and small paint brushes. If the number of big and small paint brushes are equal, identify which of the following can be the number of small and big paint brushes. Use the ‘make a $10$’ strategy to solve.

• A. $7$
• B. $5$
• C. $8$
• D. $6$

Answer 1

The correct option is C $8$

Say: Let’s read the question.

Ask:
$\bullet$ What do we need to find out?
Ans: We need to find out which number when subtracted from $16$ will give the same number as the difference.
$\bullet$ If we use make a ten strategy, what number do we need to subtract from $16$ to make it $10$?
Ans: $6$ because $16–6=10.$
$\bullet$ Can $5$ be the correct answer?
Ans: No, because $16–5=11.$ So $5$ when subtracted from $16$ do not give $5$ as the difference.
$\bullet$ What will be the difference if we subtract $7$ from $16$ ?
Ans: If we break down $7$ into $6$ and $1,6$ is subtracted from $16$ to make $10.$ Then, we subtract $1$ from $10$ to get $9$ as the answer. $16–7=9$
$\bullet$ Do you think $16–8=8$?
Ans: If we break down $8$ into $6$ and $2,6$ is subtracted from $16$ to make $10.$ Then, we subtract $2$ from $10$ to get $8$ as the answer. So, yes, $16–8=8.$
$\bullet$ Do you think $16–6=6$?
Ans: No, $16–6=10.$
$\bullet$ How many big and small paint brushes are there?
Ans: The number of big and small paint brushes is $8$ each.
Hence, option C is the correct answer.

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

Probing Question:
Q. Is there any number other than $8$, which when subtracted from $16$ will give the same number as the difference?
A: No. The next number after $8$ is $9.9$ when subtracted from $16$ gives $7$ as the difference. So, the numbers next to $9$ will give even smaller numbers than $7.$