Key words, whole numbers, natural numbers, operations, working with numbers, estimating, rules for rounding off to nearest 5, 10, 100, 1000, even & odd numbers, relations, symbols, properties, number sequences, number lines, brackets first, cumulative properties, associative properties, distributive properties, sum, difference, product, quotient, inverse operations, calculations with large numbers, transfer numbers with remainders, multiples & factors, composite & prime numbers, LCM,