Maths question in Japanese

[Lothor]

I've just done an impromptu maths lesson with a friend's JHS year 3 daughter and was sent a couple of pages of a textbook, and wasn't quite sure what the questions were asking.
The maths itself is straightforward, it's about plotting the graph of the linear function (1次関数) y=3x+1.

The question itself introduces the function, gives a table of x and y values and a picture of the graph itself.
The question has two parts.
1) 1次関数ｙ＝３ｘ＋１の変化の割合を答えなさい。
2) 直線 ｙ＝３ｘ＋１では右へ１進むと、上へどれたけ進みますか。

2) Seems to be just asking how much the line goes up when x is increased by one, which is 3, but I was confused by 1). Is it just asking the same thing - i.e., 変化の割合 is the proportional change - y is going up three times as quickly as x?

 

[Toritoribe]

Yes, both questions are asked about the same thing. Are "1)" and "2)" written in the original text? If not, it seems to me that's a single question where #2 is just a clarification about what 変化の割合 means exactly.

 

[Lothor]

Thanks Toritoribe. Yes, I copied out the text from the textbook. I think they were separate questions (the native Japanese speaking girl I was teaching thought so too), but the use of leading questions to explain a point (here that y going up by 3 when x goes up by 1 means that y goes up three times as quickly as x), is quite common when teaching mathematics.

 

[Toritoribe]

I see. Then, yes, those are indeed two questions. I think there is another possibility where other questions about 変化の割合 could appear later in the textbook, for instance, asking about 変化の割合 of a quadratic function, showing the readers/students that 変化の割合 differs depending on the choice of the two "x"s, and letting them think about the difference between the two functions.