Explain that in partial products multiplication you put the numbers one on top of the other. Then you multiply them together by calculating from left to right. Explain that you put the larger number on top and the other number underneath. With partial products you work from left to right. So you start by multiplying the hundreds numbers. You multiply these together. Then you multiply then tens and then the ones. You put all of these answers into the chart and write down the intermediate problems. If you add all the numbers in the chart together, you have the final answer. You put this answer at the bottom of the chart. Next there is a problem in a chart, each one of which with a different row marked in yellow. Ask the students if they know which intermediate problem belongs with each colored row. This is how you check if the students know what steps they need to take. After this you explain that if you have a multiplication problem with 0 you don't have to write down the answer. When you multiply a number by 0, the answer is always 0. Next you show a chart for which the intermediate steps need to be filled in. Have the students write these numbers down and hold them up, so that you can check their answers. Then practice partial products with two problems, the first one of which has the chart filled in and the other chart still must be filled in.
Check whether the students can multiply partial products by asking the following questions:
- Why is it useful to be able to calculate partial products?
- What do the letters T H T O mean?
- Where do you always start when calculating partial products?
- Solve this problem using partial products: 330 × 6