<?php

function floorLikeInExcel($number, $significance) {
  return $number - fmod($number, $significance);
}

echo floorLikeInExcel(3.7, 2) . PHP_EOL;
echo floorLikeInExcel(-2.5, -2) . PHP_EOL;
echo floorLikeInExcel(2.5, -2) . PHP_EOL;
echo floorLikeInExcel(1.58, 0.1) . PHP_EOL;
echo floorLikeInExcel(0.234, 0.01) . PHP_EOL;