Build a Number

Build a Number is a Grade 4 decimal place value activity that challenges students to create different numbers from the same set of digit cards and a decimal point. With four digits in hand, students build the largest and smallest possible values, make numbers within given intervals, and create numbers that round to specific targets. Each prompt changes what “best” placement means.

Use it when you want students reasoning about decimal place value, comparison, and rounding rather than following a single procedure. Ask them to explain why a digit belongs in a particular place and how moving the decimal point changes the value. Create a free Find a Math Game account to generate teacher-ready lesson support for Build a Number. Free accounts include 3 lifetime lesson generations with no credit card required.