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Mathematics Exercises
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KONG Ching-wah
1
A case
7x + 4x =11x
mx + nx =(m + n)x
7x + 4x =
15x + 23x =
11x + 36x =
38x + 25x =
14x + ax =
ax + bx =
2
Assignment is:
- By order
- No choice
- Routine work
- Boring
- Too easy/too difficult
- Not align with assessment
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12 -35
=
23 + (-37)
=
-65 - (37)
=
-28-(-39)
=
-6 +(-77)
=
-16 +(-37)
=
-37 -(-18)
=
18 - (-7)
=
-36 - (-57)
=
(-36) - (-57)
=
-47 -(-18)
=
26 - (-47)
=
-36 - 57
=
-16 - (-37)
=
-22 -37
=
4
-28-(-39)
=
5 – 2 = _____
5 – (-7) = _____
5 – 1 = _____
4 – (-7) = _____
5 – 0 = _____
3 – (-7) = _____
5 – (-1) = ____
2 – (-7) = _____
5 – (-2) = ____
1 – (-7) = _____
5 – (-3) = ____
0 – (-7) = _____
5 – (-4) = ____
-1 – (-7) = _____
5 – (-5) = ____
-2 – (-7) = _____
5 – (-6) = ____
-3 – (-7) = _____
5 – (-7) = ____
-8 – (-12) = ____
8 –(-12) = ____
-18–(-24) = ____
18–(-24) =____
5
28
+
-36
-
35
12
-
-26
+
-17
-
29
-22
-
52
+
-33
+
13
-
-19
6
[


1
4
7
4
－ 
[
-5
1
8
2
](
/

1
16
2
3
)
]
7
4ab + 3a2b + 2ab
Use
, and
to divide
the following expressions
into three groups.
xy
3x2y xy2
3x2y
-23x2y
7xy
-5xy
4xy
2xy2
-2x2y
16xy
43x2y
-16xy
5xy2
-3x2y
25xy
-19xy2
-11xy2
89xy2
-34x2y
-20x2y
8
2ab + 3a2b
How many “7”s are there?
2(7) + 3(7) = ___________
How many “x” are there?
2x + 3x = _____________
How many “xy” are there?
2xy + 3xy = ___________
Can we add them up?
2xy + 3x2y = ___________
= ___________
9
(4x － 3) + (－7x ＋ 9) =
2+5=
2x + x =
1+5=
2x + (-x) =
0+5=
2x + (-2x) =
-1 + 5 =
2x + (-3x) =
-2 + 5 =
2x + (-5x) =
Group the like terms.
(3x2+5x-8) + (-5x2-7x-6) =
10
Find the area of sector OAB
A
The area of sector OEF is ?
O
120o
6cm
E
O
90o 3cm
B
F
Find the area of the
shaded part.
E
120o = ------- of a circle ?
O
90o
3cm
120o
F
11
Find the total surface area of the following object.
3cm 3cm
3cm
3cm 3cm
3cm
12cm
4cm
Area
No.
of
piece
Total
Area
12cm
4cm
4cm
3cm
Dimension
4cm
3cm
12
Find the total surface area of the following object.
3cm 3cm
3cm
12cm
4cm
4cm
3cm
13
Divided by 2
A Story Mode
I can only do the
operations of “multiply
by 2” and “divided by 2”
and I can do the
multiplication of all
numbers. This is the
way I do 25(47)
Multiply by 2

25*
47
12
94
6
188
3*
376 
1*
752 
47 + 356 + 752 = 1175
25(47) = 1175
1. Find the way that John did his calculation.
2. Why it works in this calculation?
John
3. Is this method applicable to all operation of
multiplication of two numbers?
14
Believe or not?
When the sum of all the digits in a number is
divisible by 3, this number is divisible by 3.
Do you believe? Give your reason.
15
The Design:
- Of own learning
- Of own choice
- Learning task
- Variety
- Suitable challenge
- Cross topics
- Learn new things and strengthen the old.
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