Do you have any tips as to how to get kids to sit down and work on math stuff again?

I teach high school right now. I ask students in each class what their math experiences have been; I give them space to vent, and make it okay to say, "I hate math." In every class I've had, there's also been someone who says, "I love math." We then talk about what has worked for people and what hasn't. I explain much of what I wrote in the comment above; many students have been blaming themselves for years of failure, and have never realized that weren't offered a way back into math. On the other hand, some students have blamed everyone but themselves and they need to start taking responsibility for themselves, and we have that honest conversation.

Everyone needs motivation to learn anything meaningful. Motivation for students can come from a desire to earn credit and graduate, a desire to be able to do a certain job, or a desire to catch up on things they haven't understood for a long time.

I connect each student's math learning plan with their job and career goals. Most of my students are at an age where that can work, if they can see the connection. This isn't just a utilitarian approach; we also talk on a regular basis about the wonders of math, and how there are efficient strategies but there are no math "tricks". I break their work into the smallest possible chunks they can earn credit for, so they get to see academic success as soon as possible.

I'm happy to share more specific thoughts here or through email, if you have a particular situation you're trying to sort out.

That's great and major props for helping those who fell behind. I remember taking classes at the maritime college and watching all these people (who were probably way better at ships or engines than I was) struggle mightily with speed-distance-time calculations, batteries in series/parallel or Ohm's law. It was really depressing - how can our education systems fail so many people?

It should always be okay to say "I hate math." I'm a mathematician and some days I also hate math. Math is an emotional roller-coaster at all levels.

Why require the "sit down" part? As the article states, you can do math without sitting down, too.

Let them estimate how many steps a walk from A to B takes, or what distance is larger and check it by walking, ask them to count how many tiles cover a square (multiplication as a fast way of counting every tile), to estimate the number of beans in a jar and from it the weight of a single bean (combine that with Archimedes' law and let them predict whether it floats), the height of buildings (3 to 3.5 meters per floor, but also a trigonometry exercise when combined with measuring the length of its shade) etc.

You don't need to. I remember when I was a child, our family have this tradition of walking around the park after dinner. My parents would talk about work and ask about my day. And sometimes my father would throw questions like "why do you think there are 60 minutes in an hour instead of say 57" "why is 1/3 = 0.33333... is there a possibility there's a digit of 4 down the road?". I'm not sure if he come up with these question randomly or he has a system, but I still remembers a lot of them today.