35 < 36 < 37

1. Chỉ ra tính chất đặc trưng :

A = { x \(\in\) N | x \(\le\) 49 }

2. Chỉ ra tính chất đặc trưng :

B = { x \(\in\) N | 11 \(\le\) x \(\le\) 99 }

a/ 46 + 17 + 54

= ( 46 + 54 ) + 17

= 100 + 17

= 117

b/ 4.35.25

= ( 4 x 25 ) x 35

= 100 x 35

= 3500

75 + 12 + 43 + 25 + 88 + 50 + 57

= ( 75 + 25 ) + ( 43 + 57 ) + ( 12 + 88 ) + 50

= 100 + 100 + 100 + 50

= 300 + 50

= 350

75 + 34 + 43 + 25 + 66 + 57

= ( 75 + 25 ) + ( 34 + 66 ) + ( 43 + 57 )

= 100 + 100 + 100

= 100 x 3

= 300

75 + 34 + 43 + 25 + 66

= ( 75 + 25 ) + ( 34 + 66 ) + 43

= 100 + 100 + 43

= 200 + 43

= 243

34 + 23

= 23 + 34

= 57

x - 10 = 70

       x = 70 + 10

       x = 80

67, 05 + 4,2 - 56,27 

= 71, 25 - 56,27

= 14,98

1 + 2 = 3

2 + 3 = 5

3 + 4 = 7

4 + 5 = 9

75 + 15 + 25 + 85 + 60 + 50 + 40 + 50 + 10

= ( 75 + 25 ) + ( 85 + 15 ) + ( 60 + 40 ) + ( 50 + 50 ) + 10

= 100 + 100 + 100 + 100 + 10

= 100 x 4 + 10

= 400 + 10

= 410

x + 1 + 2 + 3 = 50 - 20

x + 1 + 2 + 3 = 30

x + ( 1 + 2 + 3 ) = 30

x + 6 = 30

x = 30 - 6

x = 24

x + \(\dfrac{2}{5}\) = \(\dfrac{1}{2}\)

x = \(\dfrac{1}{2}\) + \(\dfrac{2}{5}\)

x = \(\dfrac{9}{10}\)

x - \(\dfrac{2}{5}\) = \(\dfrac{2}{7}\)

x = \(\dfrac{2}{7}\) + \(\dfrac{2}{5}\)

x = \(\dfrac{24}{35}\) 

x : \(\dfrac{1}{7}\) = 14

x = 14 : \(\dfrac{1}{7}\) 

x = 98

0, 256 x 8 

= \(\dfrac{256}{125}\)

= 2, 048