Data Journalism is more related to Statistics than Maths. You need to look at trends in figures and narrate a story.
The best analogy for this is when sports commentators talk about different player statistics to make inferences about games. Similarly a data journalist uses factual data on different sectors to come up with inferences or assumptions.
For example you might calculate the total renewable energy supply in the last 10 years and compare it against total electricity demand in the same 10 years to show how the gap has increased or narrowed.
As you can see, the maths requirement is not too high level. As long as you can see patterns, connect the dots and narrate a story based on data, you can be a good data journalist without very strong maths skills.
I hope you find this information helpful see you on the next topic.