hello my name is Kylie and welcome to adding negative numbers in this video
you will learn how to add negative numbers using a number line ready to
zoom around on number line let's go by now adding numbers may seem like old
news but there are actually different kinds of numbers to add different kinds
well yes perhaps you already know different kinds like whole numbers
fractions and decimals here we'll be talking about a specific type of whole
number an integer a positive integer is any whole number greater than zero
a negative number is any number less than zero remember whole numbers or
integers are numbers without fractions or decimals by the way zero is neutral
and is neither positive nor negative most of the time you see and write
positive numbers without the plus or positive sign when you work with
negative numbers however you may see them written either with or without the
plus or positive sign to the left of the integer so just like this example 18
with the plus sign is exactly the same as 18 without a plus sign you can also
use parentheses around the integer to show its value as being positive all
three ways show exactly the same value positive 18 when we write negative
numbers we must always allow and use a negative sign to the left of the number
like this both of these show negative three when writing negative numbers in
math sentences like addition equations we also use parentheses to make sure we
don't confuse a negative number with subtraction here let me show you a
number line
on our number line you can see positive integers are greater than zero are to
the right of zero and increase to the right negative integers are less than
zero and are to the left of zero they decrease to the left yes I know it looks
odd but trust me as you move to the left the numbers are worth less even though
the numbers are going up look at this number line okay it shows how integers
moving to the right increase or go up in value and how integer is moving to the
left decrease or go down in value adding moves the number up or to the right and
subtraction moves the number down or to the left
this is the same no matter which side of the zero you are we can use this
knowledge to help us add negative numbers let's get started with this math
sentence negative five plus four use a number line to get started
always start at zero you can see the negative 5 is a negative integer this
tells us to move to the left on the number line so we moves five spaces to
the left of zero then we must add four as the number sentence tells us adding
means moving to the right on the number line so now from the negative five move
right four spaces where did you end up that's right
negative one great job here let's do another one
16 plus negative seven the first integer is 16 which means positive 16 remember
there is no sign in front of the number it shows a positive integer start a zero
and move in the positive direction or write 16 spaces then the number sentence
tells us to add a value of negative seven negative numbers move to the left
so from our spot on 16 move seven spaces to the left you should land on the nine
which nine it is the positive name because we've
landed to the right of the zero okay so this is where it can get tricky what
if you have two negative numbers to add no worries it's the same steps as the
previous two problems you can do this okay let's try negative three plus
negative four just start on the zero as always go three steps to the left for
the negative three then keep going left four spaces because you have a negative
four we end up landing on negative seven let's review this by comparing a number
line to a math map adding negative numbers is like following three
directions on a map start at zero for the first number move left to right
depending upon whether you have a positive or negative number and stay
there and last for the second number move left or right depending on whether
that second number is positive or negative
whether you land on the map or a number line you've landed on your answer ready
to try a couple of your own pause the video and try problem a and problem B
problem a five plus negative size problem B negative nine plus four I'll
show you the answers when you get back
here are the answers problem is answer is 5 plus negative 5 equals 0 and
problem B's answer is negative 9 plus 4 equals negative 5 how did you do you can
always go back and review the steps if you need more help well now that you've
taken a trip on the math number line and learned how to add negative integers
you're ready to tackle subtracting negative integers in our video
subtracting negative numbers it's always a great idea to keep practicing all your
math skills using our fun online games and quizzes until next time
always be positively clever