Multiplication & Division Flashcards

All 5 cards in this deck

What are the steps to multiply two decimals without a calculator?

e.g. $6.3 \times 2.4$

1. Ignore the decimal points and multiply the digits: $63 \times 24 = 1512$
2. Count the decimal places in the question: $1 + 1 = 2$
3. Put the point so the answer has 2 d.p.: $15.12$

How many decimal places does the answer to a decimal multiplication have?

The same total as the two numbers being multiplied.
e.g. $0.004 \times 0.32$ has $3 + 2 = 5$ d.p.

What are the steps to divide by a decimal without a calculator?

e.g. $8.46 \div 0.15$

1. Multiply both numbers by 100 so the divisor is a whole number: $846 \div 15$
2. Use short division: $846 \div 15 = 56.4$

What is the inverse operation of multiplication?

Division.
e.g. $6 \times 7 = 42$ so $42 \div 7 = 6$

True or false? Multiplying a positive number by a number between 0 and 1 always makes it larger.

False. It makes it smaller, e.g. $8 \times 0.5 = 4$.