This works if the two numbers are close together. Empty number lines can help you work out the difference between the two numbers.

Addition & subtraction strategies to solve two-digit equations using an open number line.

Explains the concept of zero in mathematics, emphasizing its role as a number that represents the empty set. It illustrates how zero is used in addition and subtraction, showing that adding or ...

Researchers from 4 projects with a problem-solving approach to teaching and learning multidigit number concepts and operations describe (a) a common framework of conceptual structures children ...