A number sentence is a mathematical sentence that includes numbers and mathematical symbols such as addition, subtraction, multiplication, division, and equality or inequality signs. It is used in primary level mathematics teaching in the US, Canada, UK, Australia, New Zealand, and South Africa. Number sentences are used to introduce students to notions of structure and elementary algebra prior to a more formal treatment of these concepts. They provide flexibility to solve a problem as compared to basic algorithms. Using sentences, students can break the numbers out to see the value of each digit. They can compose and decompose numbers by place value or use other strategies, building their reasoning and mental math skills. A number sentence without unknowns is equivalent to a logical proposition expressed using the notation of arithmetic. Examples of number sentences include:

• 83 + 19 = 102 (valid and true)
• 1 + 1 = 3 (valid but false)
• 3 + 6 < 10 (valid and true)
• 3 + 9 > 11 (valid and true)

Number sentences are simply the numerical expression of a word problem.