Mental Math Exercises
Number Sense:
1.
25 X 7 X 4 =
2.
4 X 16 =
3.
1224 ÷ 6 =
4.
Which is larger: 4.3 X 105 or 439.6 X 106 ?
5.
Find the value: 93
Could also ask to explain the strategy used to calculate the answer in #s 1-3.
1.
Determine the missing terms in the following table:
1
2
3
4
0
1
2
3
10
15
14
2.
Simplify:
3.
Evaluate the expressions below for each value of x: x  3 ,
a)
8 x
b)
12 x  6
c)
x3
d)
18  x
20
79
1
, 0.5
4
n-1
Integers
1.
( 4)  (3)  125 
2.
( 7)  ( 3)  ( 7) 
3.
200  ( 130)  ( 10) 
4.
Write the integer that is:
5.
a)
3 larger than –1
b)
2 less than 8
c)
5 larger than –4
d)
6 less than 2
Represent:
a)
–4 using 4 counters
b)
–4 using 6 counters
c)
0 using 10 counters
d)
3 using 7 counters
Probability
1.
Describe the probability of each event using words such as:
impossible, unlikely, half of the time, likely, or certain
a)
spinning a "0"
b)
spinning a "5"
c)
spinning a number divisible by 2
1
6
5
2.
d)
spinning a factor of 16
e)
spinning a "2", "3", or "6"
Describe the probability of these events occurring:
a)
winning the Lotto 6/49 jackpot
b)
being struck by lightning
c)
getting up tomorrow morning
d)
flipping "heads" with a coin
2
4
3
1)
2)
Which of the benchmarks ( 0 ,
a)
8
18
b)
9
11
c)
1
42
d)
7
30
Arrange these unit fractions in order from the least to the greatest value.
1
,
6
3)
1
, or 1 ) is each of the following fractions closest to?
2
1
1
1
1
,
,
,
4
3 8
5
Place these numbers in the appropriate position on the number line provided.
a)
0.25
0
1
2
b)
3
4
0
1
2
c)
4
8
0
1
2
d)
0.5
0
1
2
e)
9
10
0
1
2
Decimals / Percents
1.
2.
3.
5.
Each number below is near a common percent value (0%, 5%, 10%, 50%, and so on). State the
common percent nearest each number:
a)
5
24
b)
6
11
c)
1
13
d)
5
16
e)
10
12
f)
13
14
g)
0.97
h)
0.72
Calculate:
a)
25% of 80
b)
7% of 300
c)
55%
d)
15% of 30
of 60
Estimate the value of each fraction as a percent:
a)
5
21
b)
34
70
c)
87
90
d)
73
99
Estimate the value:
a)
21% of $48.99
b)
54% of $9.99
Angle Relationships
Find the values of the angles marked with a "?"
1.
121°
?
2.
?
31°
3.
?
68°
4.
?
35°
5.
118°
?