Learning a new math skill starts with demonstrating the technique and process. Match the grid to the number of digits in the multiplicands. If you are multiplying two digits by two digits, you need a grid two squares across and two squares down. A three-digit by two-digit problem takes a three-by-two grid. Divide each box diagonally from the upper right corner to the lower left corner and color every other diagonal row with a highlighter. Start at the top left corner and write one of the multiplicands across the top edge of the grid (around the outer edge, not inside the boxes), one digit per space. Write the second multiplicand down the right edge in the same manner. In each box multiply the number at the top of the column with the number at the right of the row. Write the result in the corresponding box with the ones below the diagonal and the tens above the diagonal. (if it is a single digit number, write "0" for the tens.) Add the numbers along each diagonal row from right to left and record the sums along the lower or left outer edge. Carry the tens to the next diagonal when the sum is 10 or greater. Read your answer around the outer edge from top left to lower right.
Once you have demonstrated, how to multiply with lattices, select problems from the math book, online math sites or create your own. Let the students practice using preprinted lattice grids from Super Teacher Worksheets or Mathwire. As students get comfortable using the lattice, give them graph paper and let them draw their own grids, using the lines as guides.
You can increase students' skill proficiency by turning multiplication into a game. Have students take turns creating their own problems by rolling two, three or four dice (or more for larger numbers) twice to form the two multiplicands. On his turn, the student must solve his problem using a lattice and keep a running tally of the sum of all his answers. His opponent checks his work and verifies that the answer is correct. The first player to reach 10,000 wins. You can lower or raise the goal depending on the size numbers you are using.
As students master the skill of lattice multiplication, hold a friendly team competition to increase calculation speed. Make a series of problem cards and divide the class into two teams. Armed with pencil and paper, students race to solve the problem you call out. Award points to the first team to ring their bell and call out the correct answer. You can set a 60- to 90-second time limit and give no points if no one solves it before time's up.