run this in your inspect element console

let a = 100
let x = 0
let n = 0
let s = 0
let b = false
for (let i = 0; i < a; i++) {
    n = Math.round(10+(Math.random()*10))
    s = Math.round(Math.random()*10)
    while(x!=n-s){
        x = 0
        x = prompt(`input ${n}-${s} (${a-i} to go)`)
        if (x!=n-s) i-=10
        if (x==(n-s)*(n-s)+" TERMINATE") b = true
    }
    if (b) break
}

(it doesn’t do anything malicious other than be kinda annoying)