Can someone help me I’m stumped

Question

So I’m just missing in naming this four compounds, and I’ve gotten them wrong in all my tries.

1- CH3CH2CHCH3

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CH2CH3

CH3

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2- CH3CHCHCH3

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CH2CH3

3- CH3

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CH3CHCHCH3

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CH3

CH3

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4- CH3 - C - CH3

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Answer 1

1). The longest continuous chain has 5 carbons, making it a pentane. There is methyl group (CH3) ,attached at C#3, so we name this compound 3-methylpentane

2). The longest continuous chain has 5 carbons, making it a pentane. There is a methyl group (CH3) attached to both carbons 3 and 4 so we name this compound 3,4-dimethylpentane

3). The longest continuous chain has 4 carbons making it a butane. There is a methyl group (CH3) attached to both carbons 2 and 3 so we name this compound 2,3-dimethylbutane

4). I'm not sure what you are trying to drawing here. I can't figure out what is meant by the part that looks like..

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