tansika

Hi, I am a math tuition teacher. Now my students are preparing for their final exams. They are little slow in math problems. Actually i need to check the answers fast. So i tried many online calculators. Finally found an online percentage calculator to calculate problems. But it is confused for me how it works and gives the result. Could someone explain me?

Minor chemical elements in human body and its percentage. Lithium (Li)-0.0000031% Beryllium (Be) -0.000000005 % Boron (B) -0.000069 % Fluorine (F) 0.0037% Sodium (Na) -0.15 % Magnesium (Mg) -0.05% Aluminum (Al) - 0.000087% Silicon (Si) - 0.002% Sulfur (S) - 0.25% Chlorine (Cl) - 0.15% Potassium (K) - 0.35% Titanium (Ti) - 0.000013% Iron (Fe) - 0.006% Cobalt (Co) - 0.0000021%