لوحة تحكم المعلم:
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1.3 Rounding Numbers
City B 92 km City A
92 km
City B
↵
City A
Mark wants to travel from city A to city B. The distance between them is 92 km.
How can we describe this distance to the nearest 10?
a Is it 90 km? ✓ Yes (90 km)
b Is it 100 km? ✗ No
Why?
before you answer, look at the line Number.
89 90 91 92 93 94 95 96 97 98 99 100
92 is closer to 90 or 100? 90
Exercise 1
Round the following numbers to the nearest 10?
a
26
30
e
92
90
b
73
70
f
51
50
c
87
90
g
74
70
d
35
40
h
69
70
10
John saved $280.
Dad: How much do you have, John?
John: I have $280.
Dad: Can you round the number you said to
         the nearest 100?
Can you help John answer his dad?
👨‍👦
About how much do you think? $200 or $300. Why?
$300 — Because 280 is closer to 300 than 200.
Exercise 2
Round to the nearest 100.
a
320300
d
737700
b
890900
e
679700
c
610600
f
61100
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Lily decided to travel from Amman (The capital of Jordan) to Riyadh
(The capital of Saudi Arabia). She noticed that the distance is 1446 km.
Amman Jordan 1446 km Riyadh Saudi Arabia
Round the distance to the nearest 1000. Is 1446 close to 1000, or to 2000 km?
Why?
1000 km — Because 1446 is closer to 1000 than 2000.
Exercise 3
Round to the nearest 1000.
a
24162000
d
72107000
b
46555000
e
7201000
c
61006000
f
983110000
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1.4 Even and Odd Numbers
Even numbers
Any integers that can be divided exactly by 2
2, 4, 6, 8, 10 are examples of even numbers.
Odd numbers
Any integers that cannot be divided exactly by 2
1, 3, 5, 7, 9 are examples of odd numbers.
Even Steven Even numbers end in 0, 2, 4, 6, and 8 Odd Todd Odd numbers end in 1, 3, 5, 7, and 9
Note: Number line
even numbers (count by 2s from 0) 0 1 2 3 4 5 6 7 odd numbers (count by 2s from 1)
Exercise
1 Which even number comes right after 9?
10
2 Which even number comes right after 14?
16
3 Which odd number comes right after 20?
21
4 Which odd number comes right after 33?
35
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5 Which even number comes right before 72?
70
6 Which even number comes right before 69?
68
7 Which odd number comes right before 55?
53
8 Which odd number comes right before 40?
39
If we make an addition between 2 even numbers, what will we get even
or odd? Prove your answer by examples.
Even — Example: 2 + 4 = 6 , 4 + 6 = 10
- Make this operation.
Odd + Odd = even or odd?
Prove your answer by examples.
Even — Example: 1 + 3 = 4 , 3 + 5 = 8
Odd + Even = even or odd?
Prove your answer by examples.
Odd — Example: 1 + 2 = 3 , 3 + 4 = 7
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