Question

There are $5$ blue cars and twice as many red cars than blue cars on the road.
There are __ red cars.
Identify the addition and subtraction equations.

• A. $5;5+5=10,5+5=10;10–5=5,5–10=5$
• B. $15;15–5=10,15–10=5;5+10=15;10+5=15$
• C. $10;10+5=15,5+10=15,15–5=10;15–10=5$
• D. $10;5+5=10,5+5=10;10–5=5,5–10=5$

Answer 1

The correct option is C $10;10+5=15,5+10=15,15–5=10;15–10=5$

Say: Let's read the question.

Ask:
$\bullet$ What do we have to do here?
Ans: We need to identify the number of red cars, and then identify the related addition and subtraction equations for the total number of cars on the road.

Say: Let us begin by finding the number of red cars.

Ask:
$\bullet$ How many blue cars are there?
Ans: $5$
$\bullet$ How many red cars are there?
Ans: Twice as many as the blue cars.
$\bullet$ How much is twice as much as 5?
Ans: $10$
$\bullet$ How did we find this?
Ans: By adding 5 two times, i.e., $5+5=10$
$\bullet$ So, how many red cars are there?
Ans: $10$
Say: Now let us identify the related addition and subtraction equations for the total number of cars on the road.

Ask:
$\bullet$ How many blue cars are there?
Ans: $5$
$\bullet$ How many red cars are there?
Ans: $10$
$\bullet$ What are the two addition equations that can be framed to find the total number of cars?
Ans: $10+5=15$ and $5+10=15$
$\bullet$ How do we find the difference?
Ans: By subtracting the smaller number from the bigger number.
$\bullet$ Using the same three numbers, i.e., $5,10,$ and $15$, what subtraction equation can be framed?
Ans: $15–5=10$ and $15–10=5$

Hence, Option B is correct.

WB: If required, use the whiteboard to represent the bigger number and check the smaller number as shown, and write the related addition and subtraction equations.

Probing Question:
Q. So, what are the related addition and subtraction equations that are framed?
A. Addition equations: $10+5=15$ and $5+10=15$
Subtraction equations: $15–5=10$ and $15–10=5$