Answer:
One method for calculating 83 x 1.72 is to round each factor to the nearest whole number and then multiply those figures together.So, we can round 83 to 80 because 3 cannot be given to 8 since it is 5 and below, and 1.72 to 2, because 7 is above 5 so i can +1 to 2.
80 x 1.7 = 136
So an estimate for 83 x 1.72 is approximately 136.