We also learn the traditional algorithm, but now the students understand the numbers that are carried.
When multiplying a 2-by-2 digit number, we break the numbers up first. For example, 26 becomes 20 and 6 and 34 becomes 30 and 4. Then we draw "a box" and figure out the 4 equations that would multiply each number. These are the partial products. Finally, we add the partial products to find the final product.
Common fourth grade mistakes are:
1. Creating the 4 correct equations.
2. Basic multiplication fact errors.
3. Making mistakes in addition.
Ways to help:
1. Reminding students that their equations should always have a number from the top and one from the side.
2. Helping them with basic multiplication by encouraging them to do REFLEX or other fact games.
3. Being sure that they line up their numbers correctly when adding.
4. Asking if their answer is reasonable by rounding the original equation.
These will certainly assist in success with multiplication of larger numbers.
Please ask your child to explain how they are multiplying. Allowing them to be the teacher will reinforce skills learned in class and help you to understand how they are learning.