Marcus wants to use a model to determine the difference
−
8
−
3
(
+
3
)
. He starts with 8 negative counters.
The figure shows 8 negative counters inside a closed shape.
He wants to add 3 positive counters to the model without changing the value. How can he do that?
A.
add 3 positive counters
B.
add 3 positive counters and take away 3 negative counters
C.
add 3 negative counters
To determine the difference -8 - 3(+3), Marcus can utilize a model involving counters to visualize the problem. Let's break down the options:
A. Adding 3 positive counters: If Marcus simply adds 3 positive counters without considering the existing negative ones, it wouldn't accurately reflect the given expression. We need to account for the negative counters as well.
B. Adding 3 positive counters and taking away 3 negative counters: This option takes into consideration both the positive and negative counters. By adding 3 positive counters, Marcus is increasing the value by 3. However, to ensure the model doesn't change the overall value, he should also remove 3 negative counters. This would effectively balance the positive and negative counters, ensuring the model accurately represents the given expression.
C. Adding 3 negative counters: This option doesn't address the requirement of adding 3 positive counters. Additionally, adding 3 more negative counters would increase the negative count and change the overall value, making it inconsistent with the given expression.
Therefore, the correct answer is B. Marcus should add 3 positive counters and take away 3 negative counters to accurately represent the difference -8 - 3(+3).