1. Estimate your answer by rounding off to the nearest 10 and
   then calculate.
   a. 28 x 30
   b. 16 x 40
   c. 37 × 50
   4. Calculate by using the method you like best.
   a. 27 x 15
   b. 31 x 17
   c. 26 × 15
   26 children in a class. Each child pays R20 for a new
   book. How much did they pay altogether?