# 3rd grade math Unit 2m

## 20 terms

### Turn-around-facts

Numbers can be added or multiplied in either order

### Number family

same as fact family

### fact family

1. a set of related addition and subtraction facts 2. a set of related multiplication and division facts

### Fact extensions

Using what you know about smaller numbers and applying it to larger numbers such as: 5 + 8 = 13 so 50 + 80 = 130.

### Function machine

An imaginary machine used in EVERYDAY MATHEMATICS to change numbers according to a given rule.

### Input

The starting number in the function machine.

### Output

The ending number in the function machine.

### Number model

A group of numbers and symbols that shows how a number story can be solved.

### Parts-and-total number story

A number story in which two parts are combined to find a total.

### Change diagram

A diagram used in EVERYDAY MATHEMATICS to model situations in which quantities are either increased or decreased by addition or subtraction.

### Change number story

A number story in which an amount is increased ( a change-to-more-story) A change diagram can be used to keep track of the numbers and missing information in such problems

### Deposit

When money is placed into

### Withdrawl

When money is taken out

### Comparison number story

A number story in which two quantities are compared.

### Partial-sums method

One method for solving addition problems

### Counting up method

When you add a number or numbers to an existing number to make it easier to work with