Shortcutting Multiplications
2
The number of cycles required for a multiplication
can be minimized if the operator enters the factor
with the largest sum of digits as the multiplicand.
Example 12: 987
Í
34 or 34
Í
987?
(1)
Set 9874, multiply, enter 3, multiply and
press total. Total number of cycles: 7 (3 + 4)
(2)
Set 347, multiply, enter 8, multiply, enter 9,
multiply and press total. Total number of
cycles: 24 (7 + 8 + 9)
Example 13: 123
Í
89 or 89
Í
123?
(1)
Set 1239, multiply, enter 8, multiply and
press total. Total number of cycles: 17 (8 + 9)
(2)
Set 893, multiply, enter 2, multiply, enter 1,
multiply. Total number of cycles: 6 (1 + 2 + 3)
On the other hand, if the multiplier has many digits,
the process can become longer from pressing many
keys.
Example 14: 1000001
Í
45 or 45
Í
1000001?
(1)
Set 10000015, multiply, press 4, multiply and
press total. Cycles: 9. Keys pressed: 11.
(2)
Set 451, multiply, enter zero and multiply
five times, enter 1, multiply and press total.
Cycles: 7. Keys pressed: 16.
2
Does not apply to the Elettrosumma 22
