Question

strona 32

Mnożenie i dzielenie ułamków przez liczbę naturalną.

A3 Oblicz.

a) 3x1 2/5=

b) 2x8 1/3=

c) 8x3 2/9=

d) 2 7/8x3=

e) 4 2/5x3=

A4 Oblicz.

a)5/6 liczby 13: 5/6x13=

b)3/7 liczby 42: 3/7x42=

c)7/8 liczby 24: 7/8x24=

d)1 3/4 liczby 20: 1 3/4x20=

strona 33

Mnożenie i dzielenie ułamków przez liczbę naturalną.

B3 Oblicz.

a) 5x3 4/5= b) 11 1/2x4=

c) 9x2 3/7= d) 4 5/8x3=

e) 6x3 5/18= f) 2 7/12x 8=

B4 Oblicz.

a) 4/5 liczby 90:

b) 2/20 liczby 55:

c) 1 5/8 liczby 144:

d)4 5/8 liczby 14

Answer 1

A3

a)  3 *1i2/5= 3*7/5 = 21/5 = 4 i1/5

b)  2 * 8i1/3 = 2 * 25/3 = 50/3 = 16 i 2/3

c)  8 * 3i2/9 = 8*29/9 = 232/9 = 25 i7/9

d)  2 i7/8 * 3 = 23/8 *3 = 69/8= 8 i5/8

e)  4i2/5 * 3 = 22/5 *3 = 66/5 = 13 i 1/5

 

A4

a) 13:5/6 *13 = 13*6/5 *13 = 78/5*13 =1014/5 = 202 i 4/5

     1014/5 *5/6 = 169/1 * 1/1 = 169

 

b) 42:3/7 *42 = 42*7/3 *42 = 14 *7/1 *42 = 4 116

     4 116 * 3/7 = 588 *3/1 = 1 764

 

c) 24 : 7/8 * 24 = 24 * 8/7 *24= 192/7 *24 = 4608/7 = 658 i 2/7

    4 608/7 * 7/8 = 576/1 * 1/1 = 576

 

d) 20: 1i3/4 *20 = 20 : 7/4 * 20 = 20* 4/7 *20 = 80/7 *20 = 1600/7 =228 i 4/7

     1600/7 * 1i3/4 = 1600/7 * 7/4 = 400/1 * 1/1 = 400

 

B3

a) 5 *3i4/5 = 5* 19/5 = 1/1 * 19/1 = 19

b) 11 i1/2 *4 = 23/2 *4 = 23/1 *2 = 46

c) 9 *2 i3/7 = 9* 17/7 = 153/7 = 21 i 6/7

d) 4i5/8 *3 = 37/8 * 3 = 111/8 = 13 i 7/8

e) 6 *3i5/18 = 6 * 59/18 = 1 * 59/3 = 59/3 = 19 i 2/3

f) 2 i7/12*8 = 31/12 *8 = 31/3 * 2 = 62/3 = 20 i2/3

 

B4

a/   4/5 * 90 = 360/5 = 72 

b/  55 * 2/20 = 110/20 = 5 i 10/20 = 5 i1/2

c/  144 * 1i5/8 = 144 * 13/8 = 18 *13/1 = 234

d/ 14 * 4 i 5/8 = 14 * 37/8 = 7 * 37/4 = 259/4 = 64 i3/4