I launched an educational calculator that blew up in Spanish, but it's a failure in English. What am I doing wrong?

I wanted to share my experience with a project that's got me puzzled.

A few months ago, I launched a web/app calculator specialized for kids in the Spanish-speaking market. The idea is simple: it shows step-by-step solutions for basic math operations (addition, subtraction, multiplication, and division), helping kids understand the process instead of just giving them the answer. From the start, the site saw incredible growth—10k users in just two months with barely any promotion, and since then, it has grown steadily, reaching 200k monthly users.

Given this success, I thought it made sense to adapt the tool for the English-speaking market (https://mathyc.com/calculator/). I translated the site, made some adjustments… but it hasn’t gained traction. Nothing close to the organic growth I saw in Spanish.

I’m wondering: do kids in English-speaking countries learn math differently? Are there differences in how math operations are presented? Or is this just a visibility problem, and I should be focusing my strategy differently?