#### Answer

The number of elements belongs to at least one of these sets = 34.

#### Work Step by Step

From the given Venn diagram,
the regions I, II, III, IV, V, VI, VII represents the number of elements belongs to at least one of given sets.
It's given from the Venn diagram that,
The number of elements belongs to region I = 5
The number of elements belongs to region II = 1
The number of elements belongs to region III = 6
The number of elements belongs to region IV = 2
The number of elements belongs to region V = 7
The number of elements belongs to region VI = 3
The number of elements belongs to region VII = 10
Therefore the number of elements belongs to at least one of these sets = 5 + 1 + 6 + 2 + 7 + 3 + 10 =34.