Subtract
3 − 7
-4
35 + x = 90
55
2x − 60 = 30
45
32 = 9 52 = 25 112 = 121 172 = 289
The square of an odd number is an odd number.
If an object is red, then it is not blue.
true
8 − ( − 2)
10
x − 34 = 146
180
180 + 5x = 360 − 4x
20
42 = 16 82 = 64 142 = 196 202 = 400
The square of an even number is an even number.
If an object is not red, then it is not blue.
false
15 − ( − 18)
33
3x = 180
60
(x + 6) + 3x = 90
21
2 + 5 = 7 15 + 4 = 19 22 + 13 = 35 14 + 37 = 51
The sum of an odd number and an even number is an odd number.
If an object is not blue, then it is not red.
false
37 − 48
-11
-x/3=17
-51
(3x + 1) + (2x − 6) = 180
37
5 × 10 = 50 13 × 10 = 130
18 × 10 = 180 23 × 10 = 230
The product of any number and 10 is a number that
ends in zero.
If an object is blue, then it is not red.
true
WEATHER At 7 P.M., the temperature was 4°C. By 8 P.M., it had
increased 2°C. By 9 P.M., it had decreased 1°C. By 10 P.M., it had
decreased 15°C. What was the temperature at 10 P.M.?
-10 degrees celsius
GEOGRAPHY Russia, the largest country in the
world in terms of area, occupies 6,592,800 square
miles. The difference in area between Russia and
Canada is 2,740,991 square miles. Write and solve
an equation to find the area of Canada.
x + 2,740,991 = 6,592,800; 3,851,809 mi2
WEIGHTS The difference between the weight of
3 gallons of liquid and 5-pound brick is 19 pounds.
Write an equation to represent this situation. What
is the weight of 1 gallon of the liquid?
3g −5 = 19; 8 lb
12→1 + 2 = 3 24→2 + 4 = 6
36→3 + 6 = 9 132→1 + 3 + 2 = 6
If the sum of the digits of a number is divisible by 3,
then the original number is divisible by 3.
Rewrite this statement as a true if-then statement.
An even number is divisible by 2.
If a number is even, then it is divisible by 2. If a
number is divisible by 2, then it is even.