__Simple Machines __

** simple machines- **tools that help us do work. Simple machines make work easier for us changing the amount of force (pushing or pulling) needed to do certain kinds of work.

** incline plane- **flat, slanted surface.

** pulley- **a grooved wheel with a rope around it.

** screw- **Inclined plane twisted in a spiral.

__ wedge-__ two inclined planes back to back.

** wheel & axle-** wheel and a bar that passes throught he center.

** compound machine- **two or more simple machines put together.

** work- **the use of force to make something move.

** lever- **a bar or a plank with a fulcrum.

__Place Value / Rounding__

** digits**- Any symbol or number (0, 1, 2, 3, 4, 5, 6, 7, 8, or 9) used to show a number

**= **-** **Is equal to.

** estimate**-To find an answer that is close to the exact amount.

**-A way to write numbers that shows place value of each digit**

__expanded form__**253 = 200 + 50 + 3**

*Examples:* >** - is greater than**** Example:** 6 > 4

6 is greater than 4.

<** - is less than** *Example**:* 3 < 7

3 is less than 7.

** numbers ** - describe quantities or values

** numerals**-symbols used to represent numbers

** periods **-Each group of three digits in a place value chart; periods are typically separated by commas in a multi-digit number.

**Example:**the hundreds period or the thousands period;

85,643,900 has three periods.

** place value** - the value given to a digit by its place in a number.

** standard form- **A way to write numbers that shows only its digits

**3,540 standard form**

*Example:***difference **- The answer to a subtraction problem.

*Example:* 8 - 5 = 3

3 is the difference.

**difference**

** estimation**- an approximate or rough calculation, often based on rounding.

** round**-to drop or zero-out digits in a number and change the digit in a specified place using the following rules:- if the digit in the first place after the specific place is 5 or more, add 1 to the digit in the specified place. This is rounding up.- If the digit in the first place after the specified place isles than 5, do not change the digit in the specified place. This is rounding down.- If directions do not state which place to round to, then the implication is to round to the greatest place. The only exception is rounding to the nearest whole dollar.

**Examples:** 374 370 (nearest ten)

or

374 400 (nearest hundred)

**Examples:**

__sum__**- **The answer to an addition problem *Example:*** 12 + 7 = 19The sum is 19.**

__Water Cycle__

__evaporation-__ the process in which water particles change fromliquid to gas

__Solid-__ a state of matter that has definate shape and takes up a definite amount of space

__condensation-__ the process in which water particles change from gas to liquid

__water vapor-__ gas in Earth's atmosphere

__liquid-__ a state of matter that takes up a definite amount of space but has no definite shape.

__ cloud-__ a mass of tiny droplets of condensed water in the atmosphere

__precipitation-__ water in the atmosphere that falls to Earth as rain, snow, sleet, and hail

__gas-__ a state of matter that does not take a definite amount of space but has a definite shape