Transcript Lattice Multiplication - West

Lattice Multiplication
One option to solve multi-digit
multiplication problems
This is the problem!
47
X 23
What do I do?
I haven’t even learned my 12’s yet!
Let’s try using the Lattice Method
First we need to draw a rectangle
A square is a type of rectangle!!
Next we need to divide the rectangle into
four squares (since there are four digits in
the problem).
Now we need to add the numbers. The first
number goes on top (one digit for each column);
The second number goes on the right side (one
digit for each row).
4
7
2
3
Now we add the diagonals (starting in upper
right corner of each square).
4
7
2
3
Now, we get to do math . We need to multiply
the digits and place the products in the boxes.
The 10’s digit goes in the top half and the one’s
go in the bottom half. If no digit put a zero in its
place.
4
7
0
1
8
1
4
2
1
3
2
2
Now we add along the diagonals to get our
answer.
4
1
0
7
01 1
8
4
1
2
2
1
8
1
2
3
Write the answer, use sums going counter
clockwise.
4
1
0
7
0
1
8
1
4
2
1
3
2
2
8
47 X 23 = 1,081
1