Lattice multiplication takes the place of traditional multiplication, making it more fun for kids to learn how to multiply large numbers. It is also an easier way for some students to learn multiplication, particularly of large numbers. This method is easily used for multiplying decimals as well. Students draw a grid and write the two numbers to be multiplied on the top and right side of the grid. Then multiply each digit of each number across the grid and write the result within the grid itself. The resultant digits are added together for the final answer.
Separate the class into groups of three of four depending on the class size. Each group gets one deck of cards with numbers 0 through 9 (four of each number with four cards dealt each round) four index cards with the numbers 0.1, 1, 10 and 100, and two poker chips per player. The game is played by drawing one index card as the target number. Each player must arrange his own cards and poker chip (which acts as the decimal) to get as close to the target number as possible. The closest player wins that hand and takes all the cards played. This is repeated for each index card (four rounds total) and the player with the most cards at the end wins.
Have each student create their own bingo cards, marked with both whole and decimal numbers 1 through 10 (for example, 1.5, 2.7, 5, 9.6, etc.). Choose and announce two numbers to be multiplied (such as 1.2 x 2.4). The students who have the correct number on their cards (in this case, 2.8), can then place a bingo marker on the number.
This activity uses the traditional memory game and incorporates multiplying decimals. Create a large board with index cards upside down in an even grid. The students then take turns choosing and turning over two cards, trying to find a matching pair. Matching pairs would be in this fashion: one card with two numbers to be multiplied together (such as 10 x 2.5) and the matching card would be the answer to that equation (in this example, 25). Each student takes a turn until the board is cleared.