To find the correct number line for $585 - 368$, let's break down the subtraction using place value (hundreds, tens, and ones). This matches the "jump" method shown in the diagrams.
Step 1: Start at the beginning number.
The problem starts with
585. Look at the rightmost point on each number line. All three options start at 585, so this doesn't help us eliminate any yet.
Step 2: Subtract the hundreds.
The number we are subtracting is 368. The digit in the hundreds place is 3, which means 300.
$$585 - 300 = 285$$
So, the first big jump backwards should land on
285.
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Top option: Lands on 258. (Incorrect)
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Middle option: Lands on 285. (Correct so far)
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Bottom option: Lands on 285. (Correct so far)
We can eliminate the top option because $585 - 300$ is not 258.
Step 3: Subtract the tens.
Now we are at 285. The next digit in 368 is 6, which means 60.
$$285 - 60 = 225$$
So, the next jump backwards should land on
225.
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Middle option: The jump is labeled "-80" and lands on 205. This is incorrect because we need to subtract 60, not 80. Also, $285 - 80 = 205$, but that doesn't match our problem.
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Bottom option: The jump is labeled "-60" and lands on 225. This is correct because $285 - 60 = 225$.
We can eliminate the middle option. Let's verify the last step for the bottom option just to be sure.
Step 4: Subtract the ones.
Now we are at 225. The last digit in 368 is 8.
$$225 - 8 = 217$$
So, the final small jump backwards should land on
217.
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Bottom option: The jump is labeled "-8" and lands on 217. This is correct.
Conclusion:
The bottom number line correctly shows the steps:
1. Start at 585.
2. Subtract 300 to get to 285.
3. Subtract 60 to get to 225.
4. Subtract 8 to get to 217.
Final Answer: The third number line (the bottom one)
Parent Tip: Review the logic above to help your child master the concept of sal 3 digit subtraction.
