Number Composition and Decomposition

Understanding that numbers can be decomposed in multiple ways builds the flexible thinking needed for efficient mental computation.

• Framework: Montessori
• Unit: Mathematics
• Learning area: Number Concepts
• Level: Ages 3-5

Objectives

• Break numbers into parts
• Understand multiple representations
• Build flexibility with numbers

Materials

• Counters
• Part-part-whole mats
• Number cards
• Recording sheet

Instructions

1. Present 5 counters. 2. 'How many ways can we split 5 into two groups?' 3. Try: 5+0, 4+1, 3+2. 4. Record all ways on part-part-whole mat. 5. 'Are 2+3 and 3+2 different or the same?' 6. Try decomposing 6, 7, 8. 7. Look for patterns.

Educator tip

Systematic working (0+5, 1+4, 2+3...) helps children find all combinations. Model this approach.

Assessment

Child finds all ways to decompose numbers 5-10 into two parts.

More from Mathematics

• Ordinal Numbers
• Rounding to Nearest Ten
• Even and Odd Patterns in Addition
• Capacity and Volume Exploration
• Temperature Reading
• Number Detective Game
• Mathematical Story Creating
• Mathematical Patterns in Nature