Its Tail
A sperm cell has a small agile tail which swings to and fro to push the cell forward. This tail helps it to move. Unlike the sperm cell the egg cell doesn't move since when the sperm cell unites with it the food is provided by the egg cell.
A sperm and an egg.
the egg is larger than the sperm cell
A sperm cell swims to the egg by using its tail, called a flagellum, to propel itself through the female reproductive tract. The tail moves in a whip-like motion to push the sperm forward towards the egg. Additionally, chemicals released by the egg help guide the sperm in the right direction.
The uniting is known as fertilisation of the egg by the sperm.
egg by far
Twenty-three chromosomes are in a cell that is formed from a sperm and egg cell.
FERTILIZATION
The fusion of a sperm and egg cell results in the formation of a new individual derived from their gametes.
Egg cells are the biggest: you could only fit one on the head of a pin. But I'm not sure if a sperm cell is bigger than a red blood cell or vice versa.
A sperm fused with an egg
A sperm cell is used to fertilize an egg from a female. The combination of the sperm and the egg produces a fertilized egg which will become a new individual.