In mathematics education, a number sentence is an equation or inequality expressed using numbers and mathematical symbols. It is a combination of numbers and mathematical operations that children are often required to solve. Number sentences are used to introduce students to notions of structure and elementary algebra prior to a more formal treatment of these concepts. They are introduced at the elementary school level and build on what children will have already learned about number bonds. Examples of number sentences include:

• 83 + 19 = 102 (valid number sentence that is true)
• 1 + 1 = 3 (valid number sentence that is false)
• 3 + 6 < 10 (valid number sentence using a less than symbol)
• 3 + 9 > 11 (valid number sentence using a more than symbol)

Number sentences can be used to solve problems and 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.