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Addition & subtraction strategies to solve two-digit equations using an open number line. In this lesson, students go over using different addition and subtraction strategies to solve two-digit ...

When you estimate a number you decide approximately, or roughly, how big that number is. To estimate accurately, you need to have a good understanding of the value and order of numbers. A number line ...

As children in Western cultures grow, they learn to place numbers on a mental number line, with smaller numbers to the left and spaced further apart than the larger numbers on the right. Then the ...