Odpowiedź:
d) 2 1/3 : 0,8 = 7/3 ÷ 8/10 = 7/3 × 10/8 =
= 70/8 = 8 6/8 = 8 3/4 = 8,75
e) 5,2 * 2/7 = 5 2/10 × 2/7 = 5 1/5 × 2/7 =
= 26/5 × 2/7 = 52/35 = 1 17/35
f) 0,6 : 2/3 = 6/10 ÷ 2/3 = 3/5 ÷ 2/3 =
= 3/5 × 3/2 = 9/10 = 0,9
g) 2 3/20 + 1,27 = 2 15/100 + 1,27 =
= 2,15 + 1,27 = 3,42
h) 0,65 : 6 1/5 = 65/100 ÷ 31/5 =
= 13/20 × 5/31 = 65/620 = 13/124
i) 4,5 - 3/4 * 1/3 =4 5/10- 3/12 =
= 4 1/2 - 3/12 = 4 6/12 - 3/12 = 4 3/12 = 4 1/4 = 4,25
j) ( 1 2/5 + 0,5) : 2 = ( 1 4/10 + 5/10 ) ÷ 2 =
= 1 9/10 ÷ 2 = 19/10 ÷ 2 = 19/10 × 1/2 =
= 19/20
k) 5/8 * 4,2 - 1/4 = 5/8 × 4 2/10 - 1/4 =
= 5/8 × 4 1/5 - 1/4 = 5/8 × 21/5 - 1/4 =
= 21/8 - 1/4 = 2 5/8 - 2/8 = 2 3/8
l) 4/7 * ( 0,2 + 1/4) = 4/7 × ( 2/10 + 1/4 ) =
= 4/7 × ( 4/20 + 5/20 ) = 4/7 × 9/20 =
= 36/70 = 18/35