#### Brain Buster Multiplication

##### Difficulty:

The most difficult multiplication questions with longer decimals and numbers

Notes:

Multiply can be written as: x or *

Any number multiplied by 0 is 0 -> 200 * 0 = 0

Any number multiplied by 1 stays the same -> 200 × 1 = 200

When a number is multiplied by two we are doubling the number. 200 × 2 = 400

When a whole number is multiplied by 10 we can simply add a 0 to the end because there is one zero in 10 -> 200 × 10 = 2000

When multiplying by 100 we add two zeros to the end

Also remember the sign rules:

Positive x Positive = Positive

Negative x Negative = Positive

Positive x Negative = Negative

Negative x Positive = Negative

Multiplying decimals:

Starting on the right, multiply each digit in the top number by each digit in the bottom number, just as with whole numbers.

-0.1 (1 decimal place)

x 0.4 ( 1 decimal place)

= 0004

Place the decimal point in the answer by starting at the right and moving a number of places equal to the sum of the decimal places in both numbers multiplied. One of the numbers was negative so the answer will be negative

= -0.04