148 Speed Math for Kids
To round off to six decimal places, we look at the seventh digit,
which is a 5. If the next digit is 5 or greater, we round off upward,
so the 8 is rounded off upward to 9. Th e answer to six decimal places
is 53.071429.
To round off to fi ve decimal places, we look at the sixth digit, which
is a 9, so the 2 is rounded off upward to 3. Th e answer to fi ve decimal
places is 53.07143.
Test you rself
Try these for yourself. Calculate these to two decimal
places:
a) 4,166 ÷ 42 = (Use 6 × 7 as factors)
b) 2,545 ÷ 35 = (Use 5 × 7 as factors)
c) 4,213 ÷ 27 = (Use 3 × 9 as factors)
d) 7,817 ÷ 36 = (Use 6 × 6 as factors)
The answers are:
a) 99.19 b) 72.71 c) 156.04 d) 217.14
Long division by factors allows you to do many mental calculations
that most people would not attempt. I constantly calculate sporting
statistics mentally while a game is in progress to check how my team
is doing. It is a fun way to practice the strategies.
I like to calculate percentages for baseball and football results. You
can calculate batting averages by dividing the number of base hits by
the total number of at bats. You can also calculate a pitcher’s earned
run average or a player’s on base percentage.
Almost any game has its own statistics and calculations. Why not
try these calculations with your favorite sports and hobbies?
brent
(Brent)
#1