[stripes1776]

Tonight my daughter was showing me a number line technique for determining if fractions are equal, or if one is greater than the other.

It seems to me the purpose of this exercise is to show that number lines with different scales are not a good technique for determining the relative size of fractions.

Have they been taught how to determine the lowest common denominator and then convert the fractions to that denominator?

[Fundamentally Fair]

It seems to me the purpose of this exercise is to show that number lines with different scales are not a good technique for determining the relative size of fractions.

No. The indented purpose was to show the kids that they could use a number line to determine which fraction was greater.

Have they been taught how to determine the lowest common denominator and then convert the fractions to that denominator?

Yes. That was the second part of the lesson. They were taught to methods for working the problems, then had to work some problems with a number line and others by finding a common denominator and comparing.