You know that math paper where only a line is provided for your child to fill up his answer? Too often, my son writes the correct answer without penning down the unit of measurement. That's precious marks gone!
Just last week, my son told me his classmate lost 7 marks out of 60 in his school's prep test just because she had forgotten to write down all the units of measurement. How cruel can the school be? But I guess that's the way they mark.
Having said this, in the PSLE paper, the unit of measurement will normally be provided. That's a relief, but do get your child to make it a practice to write down the unit if it's not provided. Different schools practice different standards of marking.
Experiment #7 - Forces (Frictional Force)
Experiment #6 - Forces (Frictional Force)