Somewhere
in themathlab.com, locked with a secret password, is a treasure
page. This page has over 10 FREE gifts for you. You are
now looking at the TREASURE FINDER
page that will lead you to this password.

Read
through the page below and do what it says. Write down any parts
of the password as you find them.

You
will need paper and pencil to keep track of your mental math results.

This
treasure page's password has eleven letters in it. GOOD LUCK.

When
you KNOW the password

MULTIPLYING
BY TWO is just doubling. Simply add the number to itself. If the number
is long, you can double it in place value pieces.

EX: 753 x 2
= (700+50+3)2 or
Think:
+ 700+50+3
+. 700+50+3
-----------------
1400+100+6 = 1506
*We like to add these from LEFT to RIGHT, keeping a running total
in our heads. 1400+100=1500 and 1500+6=1506.

HERE try a few
for yourself. Click the ? to see if you are correct.
*The answer check ?'s only work in Internet Explorer.

859 x 2 = ?

427 x 2 = ?

3,941 x 2 = ?

3.43 x 2 = ?
*Don't forget to keep the decimal
in the same spot.

MULTIPLYING
BY FOUR is simply multiplying by two TWICE. You just double the number
TWICE, because 4=2x2.

EX: 32 x 4 =
Think: 32 x 2 = 64 and 64 x 2 = 128

EX:
0.45 x 4 =
Think: double 0.45 to get 0.9; double 0.9 to get 1.8

MULTIPLYING
BY EIGHT is the same as doubling THREE TIMES, because 8=2x2x2.

This trick may
take a bit of practice before your speed gets fast.

EX: 27 x 8 =
Think:
double 27 get 54
double 54 get 108
double 108 get 216

EX: 5.2 x 8
=
Think:
double 5.2 get 10.4
double 10.4 get 20.8
double 20.8 get 41.6

EX: 639 x 8
=
Think:
double 639 get 1278, then double and get 2556, then double and get 5112.

*It's fun to
challenge yourself to multiply by eight like this. Remember, you can
always check your answer by casting
out nines.

Password Clues

Use
the tricks for 2, 4, and 8 to find the answers to each problem
below IN ORDER. (Challenge
yourself to do them all mentally) Look for the answer
in the right hand column and write down the letter that corresponds
to it.

When
you KNOW the password

2 x 17 =

13 x 4 =

59 x 2 =

123 x 4 =

2 x 13.2 =

8 x 14 =

4 x 0.32 =

960 x 2 =

15 x 8 =

4 x 16.34 =

3.41 x 2 =

2 x 57.7 =

8 x 719 =

37.08 x 4 =

5.38 x 2 =

4 x 33 =

2 x 5,678 =

0.15 x 4 =

1.12 x 8 =

29 x 2 =

Now cross off every
c, r, and t. You should then see the password.

65.36 = k

10.76 = b

26.4 = o

58 = s

34 = c

492 = r

1.28 = t

11,356 = c

5,752 = e

1,920 = c

0.6 = l

6.0 = t

6.82 = r

115.4 = c

118 = m

54 = r

8.96 = l

132 = a

148.32 = y

52 = c

112 = n

120 = r

11,346 = t

When
you KNOW the password

To
learn even more of these mental math tricks try the book