Calculate negative three multiplied
by seven multiplied by 10.
As multiplication is commutative,
we could multiply the numbers in any order. We could start by multiplying
negative three by seven. Alternatively, we could multiply
seven by 10. Our first step could also be
multiplying negative three by 10.
In this question, we’ll work from
left to right and start by multiplying negative three by seven. In order to do this, we need to
remember what happens when we multiply positive and negative numbers. Multiplying two positive numbers or
two negative numbers gives us a positive answer. However, multiplying a positive
number by a negative number in either order gives us a negative answer. If the signs are the same, our
answer will be positive. Whereas if they are different, the
answer will be negative. Three multiplied by seven is equal
to 21. Therefore, negative three
multiplied by seven is equal to negative 21. The answer is negative as we’re
multiplying a negative number by a positive one.
Our final step is to multiply
negative 21 by 10. Multiplying any number by 10 moves
all the digits one place to the left. So 21 multiplied by 10 is equal to
210. This means that negative 21
multiplied by 10 is equal to negative 210. The calculation negative three
multiplied by seven multiplied by 10 is equal to negative 210. We get exactly the same answer if
we multiply seven and 10 first. Seven multiplied by 10 is equal to
70. Multiplying this by negative three
also gives us negative 210.