Multiplying Decimals Without a Calculator

This video tutorial covers two methods for multiplying decimals without a calculator: the column method and the lattice method. It explains the principle of aligning decimal points based on the number of digits in the factors and provides step-by-step instructions for each method. The video concludes with practice questions for viewers to try on their own.

What is the key principle to remember when multiplying decimals?

• The answer should have more decimal places than the factors.

• The answer should have the same number of decimal places as the total in the factors.

• The answer should have no decimal places.

• The answer should have fewer decimal places than the factors.

In the column method, what is the first step after noting the decimal places?

• Convert decimals to fractions.

• Multiply directly with decimal points.

• Add more decimal points.

• Remove the decimal points.

How do you determine where to place the decimal point in the column method?

• By guessing the position.

• By adding one more decimal place than in the factors.

• By placing it at the start of the number.

• By counting the total decimal places in the factors.

In the lattice method, what is the purpose of drawing lines from the decimal points?

• To separate the numbers.

• To find where the decimal point should be in the answer.

• To determine the size of the answer.

• To create a design.

What should you do after calculating the multiplication in the lattice method?

• Ignore the decimal points completely.

• Add the decimal points randomly.

• Draw lines from the decimal points to find their position in the answer.

• Multiply again to verify.