To decompose means to break apart. Your child has already decomposed whole numbers with number bonds, tape diagrams, and place value charts. In fourth grade, he will decompose fractions.
Three-eighths is a fraction. We can decompose three-eighths into parts using a tape diagram as the visual model. One-eighth, plus one-eighth, plus one-eighth equals three-eighths.Your child will write this as an equation. These are called unit fractions.
He will also decompose three-eighths as two-eighths plus one-eighths. Decomposing fractions into different parts helps your child to understand that one whole can be expressed in more than one way.
Sometimes your child will work with improper fractions. Ten-fourths is an improper fractions because the numerator is greater than the denominator. Your child will decompose an improper fraction by considering the denominator and pulling out one whole. Four-fourths equals one whole. After pulling out four-fourths, six-fourths remain.
But wait! He can pull out another whole! Your child knows one whole equals one, so he can now see ten-fourths equals one plus one plus two-fourths.
Practice decomposing fractions with your child so he will be ready for mixed numbers and performing operations with fractions!