As this resource is about representing operations on a number line, students who have not used a number line to solve problems may need introductory work looking at how addition and subtraction can be shown as jumps on a number line.  Introduce students to the number line using more basic addition problems like those found in NM1215 (L2) or NM1213 (L3).
Ask questions like:
"What happens if I start here and add 10?", or "How do we show the addition on the number line?"
Encourage students to just draw an approximate jump, mark the size and direction of the jump, and the new location on the number line, repeating this process until they reach the target number.  Then show them how add up all the numbers they jumped to get their answer.
Some students solve the problems using another method and attempt to represent the solution on the number line rather than showing how the solution can be reached using a number line.  In this case the lines drawn on the number line do not necessarily represent additions or subtractions.  Students may write the answer on the number line and try to draw appropriate visual lines.  For example,

Without the size of the jumps indicated there is no evidence that the number line is actually being used to solve or even represent the equation (although they have solved the equation using some other strategy).
For students who can show basic place value jumps on the number line, encourage them to use fewer jumps to solve the equation more efficiently and reflect on which strategies best suit the particular equation.  This may involve using tidy numbers or compatible numbers rather than jumps made strictly using place value partitioning, and may also involve jumping past the target number, then back to it.
For students who solved the equation using the vertical algorithm and then represented the answer on the number line, encourage them to use jumps on the number line as a tool to solve and reflect on the jumps that could make this most efficient (as above).