split_number.js

function splitNumber(n,l) {
  if ( l == 1 ) {
    return [n];
  }
  var guess = Math.random(n / l + 1) * (((n/l) / 10 ) * 10);
  return [guess].concat(splitNumber(n - guess,l - 1))
}
// Test Code
for ( var i = 0; i < 10; ++i ) {
  var test_case = Math.random();
  if ( test_case > 0.25 ) {
    test_case = Math.floor(test_case * 100);
    parts = 4;
  } else {
    test_case = Math.floor(test_case * 10);
    parts = 7;
  }
  console.log("case:", test_case, splitNumber(test_case,parts).reduce((v,a) => a += v) == test_case, splitNumber(test_case,parts).length == parts);
}