Elaine used the subtraction algorithm to subtract −17−(−3). She got the answer −14, but she does not feel confident that she is correct. Connect the expression −17−(−3) to a two-color counter model. Explain how the two-color counter model can be used to confirm whether Elaine’s answer is correct.(2 points)
-17 is blue and -3 is red
To use a two-color counter model to confirm Elaine's answer, we can use blue and red counters to represent -17 and -3, respectively.
First, we start with -17 blue counters. Then, we subtract -3 red counters from the -17 blue counters.
To do this, we remove 3 blue counters (since -3 is red) from the pile of -17 blue counters. After removing the 3 blue counters, we should have -14 blue counters remaining.
If our resulting pile matches the answer that Elaine got (-14), then her answer is correct. If there is a different number of blue counters remaining, then her answer is incorrect.
Therefore, by representing -17 as blue counters and -3 as red counters, we can physically demonstrate the subtraction process and visually confirm whether Elaine's answer is correct.
To connect the expression −17−(−3) to a two-color counter model, we can represent -17 using blue counters and -3 using red counters.
To confirm whether Elaine's answer is correct, we can use the two-color counter model. Here's how:
1. Start by representing -17 using blue counters. Place 17 blue counters on the table.
2. Represent -(−3) using red counters. Since negative of a negative is positive, we will represent -(−3) as 3 red counters. Place 3 red counters on the table.
3. Now, subtract the red counters from the blue counters. Begin by removing 3 blue counters. Count them out and set them aside.
4. After removing 3 blue counters, count the remaining blue counters. If the number of blue counters left matches Elaine's answer of -14, then her answer is correct. If the result is different, then her answer is incorrect.
By using the two-color counter model, we can physically represent and manipulate the numbers involved in the subtraction expression. This helps in visualizing and understanding the process of subtracting two negative numbers.