Year 4: Using Mixed Units Some fun and challenging work for Year 4 children working with mixed units. Each line has to add up to the same total, but the units of measurement are mixed; they might be given in kilograms and grams or litres and millilitres. The key here is to be able to add these mixed units ( e.g. 0.6 kg + 700 g) either converting all to kilograms or all to grams. Go to Year 4 Measurement