(0.3)(0.6)=0.18; also (3/10)(6/10)=18/100=9/50
(0.5)(-0.4)=-(0.5)(0.4)=-0.20; also -(1/2)(2/5)=-1/5
-0.2∙-0.7=(-0.2)(-0.7)=+(0.2)(0.7)=0.14; also (1/5)(7/10)=7/50
On a hundredth grid you can measure a rectangle with one number as the length and the other as the width. The number of squares inside the rectangle gives you the answer in hundredths. So, for example, in the first question measure out a rectangle 3 tenths by 6 tenths. The rectangle will contain 18 squares, that is, 18 hundredths.