1 decimeter = 10/0cm

1 km (km) =1000m

1 ton = 1000 kg

Perimeter of rectangle = (length+width) *2

Circumference of a square = side length *4

1 min =60 seconds

(That's all the formulas in the last semester of Grade Three, a+b=b+a ... These algorithms were learned in the next semester of Grade Four)