Zadanie 9,strona 29,Szkoła podstawowa,klasa 4 (podręcznik)

Oblicz:

a) 8 x 25             b) 125 x 16             c) 6 x 50             d) 25 x 16

12 x 25                 125 x 32                 42 x 50               24 x 125

32 x 25                40 x 125                 26 x 50               14 x 50

28 x 25                2 x 125 x 50            50 x 8                 50 x 40

WSKAZÓWKA. 4 X 25 = 100, 8 X 125 = 1000, 2 X 50 = 100,

12 X 25 = 3 X (4 X 25)

Odpowiedż:

a)

8 x 25 = 2 x (4 x 25) = 2 x 100 = 200

12 x 25 = 3 x (4 x 25) = 3 x 100 = 300

32 x 25 = 8 x (4 x 25) = 8 x 100 = 800

28 x 25 = 7 x (4 x 25) 7 x 100 = 700

b)

125 x 16 = 2 x (8 x 125) = 2 x 1000 = 2000

125 x 32 = 4  x (8 x 125) = 4 x 1000 = 4000

40 x 125 = 5 x (8 x 125) = 5 x 1000 = 5000

2 x 125 x 50 = 100 x 125 = 12500

c)

6 x 50 = 3 x (2 x50) = 3 x 100 = 300

42 x 50 = 21 x (2 x 50) = 21 x 100 = 2100

26 x 50 = 13 x (2 x 50) = 1300

50 x 8 = (50 x 2) x 4 = 100 x 4 = 400

d)

25 x 16 = 25 x 4  x 4 =100 x 4 = 400

24 x 125 = 3 x (8 x 125) = 3 x 1000 = 3000

14 x 50 = 7 x (2 x 50) = 7 x 100 = 700

50 x 40 = (50 x 2) x 20 = 100 x 20 = 2000