Final answer:
A child usually has 20 deciduous teeth, also known as primary or baby teeth, which begin to appear around 6 months of age and are eventually replaced by permanent teeth.
Step-by-step explanation:
how many deciduous teeth a child usually has is: 1) 20.
Deciduous teeth, also known as primary teeth or baby teeth, are the first set of teeth that emerge in infancy and early childhood. A normal set of deciduous teeth includes 20 teeth. These begin to appear at about 6 months of age. The incisors are typically the first to emerge, followed by the first molars, canines, and second molars. The sequence in which these teeth emerge is generally the same for most children, although the exact age at which each tooth comes in can vary.
Around the age of six, these deciduous teeth begin to be replaced by permanent teeth. By the time this process is completed, there will be a total of 32 permanent teeth, including incisors, canines, premolars, and molars. It is important to maintain good dental hygiene from early childhood to ensure the health of both deciduous and permanent teeth.