How do i add and subtract significant figures?

How many molecules are found in 1.32 mol of nacl?

Indicate whether the specified alkyl halides will form primarily substitution products, only elimination products, both substitution and elimination products, or no products when they react with sodium methoxide. 1-bromobutane 1-bromo-2-methylpropane 2-bromobutane 2-bromo-2-methylpropane

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains