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.
expanded form-A way to write numbers that shows place value of each digit
Examples: 253 = 200 + 50 + 3
> - 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
Example: 3,540 standard form
difference - The answer to a subtraction problem.
Example: 8 - 5 = 3
3 is the 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)
374 400 (nearest hundred)
sum- The answer to an addition problem
12 + 7 = 19
The sum is 19.
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