var fDesc=new Array(); fDesc[0] = "Math Blaster 4th Grade builds heavily on concepts that were covered in the first and second and third grade. Free online math games for 4th graders can be a fun way to brush up math skills that were taught earlier and get introduced to new concepts. The virtual world with cool math games here at Math Blaster is a great way to get the learning started!"; function tShowHide(id, show) { var s = document.getElementById("desc"); if ((s.innerHTML.length<=212 || show==1) && show!=2) { s.innerHTML = fDesc[id]; if (document.getElementById('m1')) document.getElementById('m1').style.display='none'; if (document.getElementById('m2')) document.getElementById('m2').style.display='none'; if (document.getElementById('more_txt')) document.getElementById('more_txt').style.display='inline'; } else { s.innerHTML = ''; } }