a)
Obw = 3cm + 10cm + 2 * 12cm
Obw = 13cm + 24cm
Obw = 37cm
b)
Obw = 2m + 5m + 2 * 4m
Obw = 7m + 8m
Obw = 15m
c)
c = (60cm - 14cm - 10cm) : 2
c = (46cm - 10cm) : 2
c = 36cm : 2
c = 18cm
d)
a = 28m - 2 * 5m - 10m
a = 28m - 10m - 10m
a = 18m - 10m
a = 8m
e)
b = 90cm - 2 * 15cm - 20cm
b = 90cm - 30cm - 20cm
b = 60cm - 20cm
b = 40cm
f)
a = 60cm - 2 * 18cm - 13cm
a = 60cm - 36cm - 13cm
a = 24cm - 13cm
a = 11cm
