This lesson features three activities to promote number sense with large numbers, fractions, and decimal operations. In the first activity, students use proportional reasoning to determine whether $1 million in $1 bills would fit in a suitcase and how much it would weigh. In the second activity, students use circular regions to develop their sense of the relative sizes of fractions between 0 and 1. In the third activity, students play a game that develops their sense of the effect that operations with decimal numbers have on the size of the answer. The website includes a lengthy and detailed discussion of the various kinds of number sense students need to develop, complete with specific examples of different levels of understanding. Activity sheets are included. (sw)

Number sense is a particularly important skill in most career technical fields, since students need to understand if and when a particular answer is logical and reasonable. Practical, on-the-job applications of mathematical concepts almost always begin with estimation and proceed to precise calculation. Students need extensive practice in comparing their estimated answer with the precise calculation. While this lesson is not specific to a particular career field, the instructor can craft similar lessons which use the elements of the field. The suitcase example can be re-written as a shipping problem while the comparison of fractions activity and the decimal game can be can be incorporated into lessons on measurement and tolerances.