Line and Box (LaB) BI version

Line and Box (LaB) is a novel
method to solve mathematical
problems involving two-digit
multiplication and any other digits.

For example, 342 x 13.
First, start calculating with

the Box (B) method.

342
X 13

X

Circle the digit “3”
so that calculations are
focused on digit “3” only.

342
X 13

X

Multiply 2 to 3 and write the
answer as 06 right below the
multiplication. The vertical line
will determine the place value.

342

X 13
06

X

Repeat the multiplication of
numbers “3” and “4” (to the left

of “2”) with digit “3”.
Then, cross out the space right
after the calculation is done with

the first row of numbers.

342

X 13
091206

X

Now, use a different shape
for example a square to mark
digit “1” which is to the left

of “3” in the second row.

342

X 13
091206

X

Repeat the multiplication steps
for the numbers “2”, “4”, “3” in
the top most row with “1” which
you have marked with a square.

342

X 13
091206

03 0402 X

Next, add up all the numbers in
the box. As there are no other
numbers to be added to 6, write

6 in the box directly

342

X 13
091206

03 0402 X

6

Add up all the numbers
according to their colours.
For example, in blue boxes,

2 + 2 + 0 equal to 4.

342

X 13
091206

03 0402 X

46

When adding up the sums from
left to right, numbers which add
up to 10 or more will be rounded
off by adding “1” to the sum of

digits to the left.

342

X 13
091206

1

03 0402 X

446

The final answer for
342 x 13 is 4446.

342

X 13
091206

1

03 0402 X

04 446

If the multiplication still
couldn’t be done using Box
method, Line (L) is the second

alternative method.

3x4=

Draw 3 vertical lines.



Then draw 4 straight horizontal
lines across the vertical lines.



Count all the interception
points. There are 12

interception points mean
3 x 4 = 12.



LaB is invented by :
Lim Wee Pu

Loo Yong Quan
Lee Xin Hui