PROBLEM “B”
Tell a student to choose any number and add 5 to it.
Multiply this result by 3.
Subtract 9.
Divide the remainder by 3.
Subtract the number that was first selected.
Now, you can give the student the result.
PROBLEM “C”
Ask a student to select two numbers, each of which is less
than 10.
Tell the student to choose either of the numbers and to
multiply it by 5.
Tell the student to add 7 to this result.
Multiply the resulting sum by 2.
Add it to the other number that was first selected.
Have the student tell you the result.
Now you can tell the student the two numbers that were first
chosen and also the one which was multiplied by 5.
ANSWERS
PROBLEM “A”
The result will always be “7” no matter what number was
chosen.
PROBLEM “B”
The result will always be 2.
PROBLEM “C”
From whatever result the student gives you, subtract 14. You
will then have a number of two figures. The two figures of this
number are the two numbers which the person selected and the
figure in “ten’s” place, that is the left-hand figure, is the
one which the student multiplied by 5.
For example, if the student says, “My result is 88”, you
subtract 14 from 88. The result is 74. The two numbers which the
student chose were, therefore, 7 and 4, and, since 7 is the
ten’s figure of 74, it is the number which he multiplied by 5.
Finding Someone’s Age
Ask the person to multiply the first number of his or her age
by 5.
Tell them to add 3.
Now tell them to double this figure.
Finally, have the person add the second number of his or her
age to the figure and have them tell you their answer.
Deduct 6 and you will have their age.
YOUR AGE - YOUR AGE - YOUR AGE
Multiply your age by 7
Now multiply it by 1,443
What do you get?
