# Math Practice #2

## I can think about numbers in many ways!

Use numbers, words, and reasoning habits to help me make sense of problems.

## Contextualize and Decontextualize

Contextualize-turn the numbers into words.

Decontextualize-words into numbers

These are examples of

## What It Is

More generally, Mathematical Practice #2 asks students to be able to translate a problem situation into a number sentence (with or without blanks) and, after they solve the arithmetic part (any way), to be able to recognize the connection between all the elements of the sentence and the original problem. It involves making sure that the units (objects!) in problems make sense. So, for example, in decontextualizing a problem that asks how many buses are needed for 99 children if each bus seats 44, a child might write 99÷44. But after calculating 2 or 11 or 2¼ or 2.25, the student must recontextualize: the context requires a whole number answer, and not, in this case, just the nearest whole number. Successful recontextualization also means that the student knows that the answer is 3 buses, not 3 children or just 3.

## Before you GO

Reason abstractly and quantitatively.