Р= 43*4=172 мм
S= 43*43=1849 мм2
12 : 3,2 + (6 - (3 7/8 - 1 5/6) * 6/7) = 8
1) 3 7/8 - 1 5/6 = 3 21/24 - 1 20/24 = 2 1/24
2) 2 1/24 * 6/7 = 49/24 * 6/7 = (7*1)/(4*1) = 7/4 = 1 3/4 = 1,75
3) 6 - 1,75 = 4,25
4) 12 : 3,2 = 3,75
5) 3,75 + 4,25 = 8
а) 2 1/10 ÷ 1 2/5 = 21/10 × 5/12=21/24= 7/8
б) 4 1/2 ÷ 5 1/4 =
5/2×4/21=20/42=10/21
в) 4 3/4÷1/4-2 = 15/4×4/1-2=13
3/14×7=3/2