# Negative by pegsplans

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```									                         The A to Z’s of Math Activities
N is for Negative Number
Background
A negative number is a number with a value less than zero. It is
usually written with a minus sign (-) in front of it. Numbers greater than
zero are positive numbers. They can be written with a plus sign (+). Any
number that is not preceded by a sign is a positive number.
In mathematical terms a minus sign (-) can also mean subtract; while
a plus sign (+) can refer to addition.
Historically, negative numbers were first written about during China’s
Han Dynasty (202 BC to 220 AD).

Materials                                Vocabulary
Activity 1                               Minus represented by –
Circle Patterns                         can mean (1) negative number or (2)
Red and green crayons                   take away, subtract
Scissors                                Negative number a number less than
Activity 3                               zero
Graph paper                             Plus represented by +
Ruler                                   Can mean (1) positive number or (2)
Positive number a number greater
than zero
Zero indicates no value

Activity 1
SET UP        circle pattern sheet, red and green crayons, scissors
Color half of the circles red and half of the circle green, cut out
the circles

Circle Patterns

OOOOOO
OOOOOO
The A to Z’s of Math Activities
N is for Negative Number

OOOOOO
OOOOOO
Activity 1   Combine Positive and Negative Numbers
Write problem on the white board
Example:    -3 + (+2)

STEP ONE          Use circles to represent the numbers
Red circles represent negative numbers
Green circle represent positive numbers
Set out 3 red and 3 green circles, next to each
other
Set out 2 red circles and 2 green circles, next
to each other

STEP TWO          Begin with -3
Remove the 3 green/positive circles
The A to Z’s of Math Activities
N is for Negative Number

STEP THREE         What is the problem asking you to do?

STEP FOUR Keep the +2
Remove the 2 red/negative circles

STEP FIVE          Partner up, remove pairs of one red and one
green circle until only one color remains

STEP SIX           What is the answer?
1
(If there were none left, the answer would be zero)
The A to Z’s of Math Activities
N is for Negative Number

Try it again
Write problem on the white board
Example:    -4 - (-1)

STEP ONE        Use circles to represent the numbers
Red circles represent negative numbers
Green circle represent positive numbers
Set out 4 red and 4 green circles, next to each
other
Set out 1 red circle and 1 green circle, next to
each other

STEP TWO        Begin with -4
Remove the 4 green/positive circles

STEP THREE      What is the problem asking you to do?
The A to Z’s of Math Activities
N is for Negative Number
STEP FOUR Take away the -1
Remove the 1 red/negative circle

STEP FIVE          Partner up, remove pairs of one red and one
green circle until only one color remains

STEP SIX           What is the answer?
is -3

+3 + (-2) = +1    -3 + (-2) = -5       +3 – (+2) = +1
+4 – (-1) = +5    +4 + (+1) = +5       -4 – (-1) = -3
+2 + (+2) = + 4   -2 + (+2) = 0        +2 – (-2) = +4

Have students work in small groups
Review problems and answers on the white board
The A to Z’s of Math Activities
N is for Negative Number
A negative negative equals a positive (Comparative to a double negative
when you speak)
A negative sign telling you what to do will change the sign of the next
number

Activity 3   Optical Illusion
SET UP       Graph paper, ruler, pencil, pen

STEP ONE             Use the ruler to draw two intersecting lines in pen
Draw the lines in the middle of the graph paper

STEP TWO            Use a pencil; mark the space where the lines
intersect 0

STEP THREE         Use a pencil; begin at the 0 and move right,
number each line +1to +11
These numbers represent values MORE than zero

STEP FOUR Use a pencil; begin at the 0 and move left, number each
line -1 to -11
These numbers represent values LESS than zero

STEP FIVE           Use a pencil; begin at the 0 and move up, number
each line +1to +11
These numbers represent values MORE than zero

STEP SIX             Use a pencil; begin at the 0 and move down,
number each line -1 to -11
These numbers represent values LESS than zero
The A to Z’s of Math Activities
N is for Negative Number

STEP SEVEN     Use the ruler and the pen to connect pairs of
numbers:
Note:
the first number represents the numbers on the left
to right line
the second number represents the numbers on the
up and down line
(left to right line, up and down line)

(+1, +11) (+2, +10) (+3, +9) (+4, +8) (+5, +7) (+6,
+6) (+7, +5) (+8, +4)
(+9, +3) (+10, +2) (+11, +1)

(-1, +11) (-2, +10) (-3, +9) (-4, +8) (-5, +7) (-6, +6)
(-7, +5) (-8, +4)
(-9, +3) (-10, +2) (-11, +1)

(+1, -11) (+2, -10) (+3, -9) (+4, -8) (+5, -7) (+6, -6)
(+7, -5) (+8, -4)
(+9, -3) (+10, -2) (+11, -1)

(-1, -11) (-2, -10) (-3, -9) (-4, -8) (-5, -7) (-6, -6) (-7,
-5) (-8, -4)
(-9, -3) (-10, -2) (-11, -1)

STEP EIGHT      Erase the pencil marks
The A to Z’s of Math Activities
N is for Negative Number

Why do the lines appear curved?