KS2 Primary Maths Age 13-17 - Calculations: Written Multiplication - Explained

The video tutorial demonstrates two methods for solving the multiplication problem 45 * 2. The first method uses short multiplication, emphasizing the importance of carrying over numbers. The second method involves splitting the numbers into parts, multiplying separately, and then adding the results. The tutorial concludes by stressing the importance of using clear and accurate methods, regardless of the approach chosen.

What is the first step in the short multiplication method for 45 * 2?

• Add 4 and 5

• Multiply 5 by 2

• Subtract 2 from 45

• Multiply 4 by 2

In the short multiplication method, what do you do after multiplying 5 by 2?

• Multiply 4 by 5

• Carry over 1

• Add 10 to 40

• Subtract 1 from 9

How do you calculate 2 * 45 using the alternative method?

• Subtract 5 from 40, then multiply by 2

• Add 40 and 5, then multiply by 2

• Multiply 2 by 40 and 2 by 5, then add the results

• Multiply 2 by 45 directly

What is the result of adding 80 and 10 in the alternative method?

• 70

• 80

• 100

• 90

Why is it important to have a clear method when solving multiplication problems?

• To ensure accuracy

• To make it faster

• To use fewer steps

• To avoid using a calculator