Using a number line, solve (-8) + (-4) + 6. Verify the associative identity of addition for integers -8, -4 and 6.

Classify the following sets as empty, singleton, finite or infinite sets:

(a) A = { }

(b) B = {50}

(c) C = {1, 4, 9, 16, 25}

(d) D = {x : x is a natural number greater than 20}

(e) E = {x : x is a negative whole number}

Multiply: 4.8 × 3.5

Find the ratio of 450 mL to 1.8 L in simplest form. Are the ratios 6 : 8 and 15 : 20 in proportion? Justify your answer.