Depending on when you went to school, the terms used when adding, subtracting and multiplying may vary. Think of a question like 52 minus 28. You might remember saying, well you can't subtract 8 from 2, so you borrow  one from the the 5 and you take 8 away from 12 (and 2 from 4). Well, do you ever pay it back? If you borrow, there is this notion that it's owed back. Thus, the mathematicians and passionate individuals that write our curriculum decided to let go of the terms like borrowing and carrying and replace it with regrouping.  Regrouping simply means exchanging tens for ten ones or hundreds for tens.  Hence, regrouping is the newer term for carrying or borrowing.  For more information, check out the video for 2 digit addition involving re-grouping. Note, in this video, the term used is grouping.

A prime number is a number that is bigger than one and cannot be divided evenly by any other number except one and itself.  This article will help you find out if a number is prime or not using the following methods:  factor trees, a calculator or divisibility. However, sometimes when dealing with large numbers, you may want to use the prime number calculator.

When numbers are quite large, you may find this website showing an expanding prime number archive currently sitting on 20 billion numbers discovered and indexed.  You can use multiple search methods to find a page
based on index or the prime number in question.  A great, free service to any math enthusiast or computer science individual.

See also: Factor Tree Worksheets and Prime Factor Worksheets.

This week I received an email with this online derivative calculator.  It supports symbolic computation of the 1st, 2nd, ... derivative of a function. While typing, the input is displayed as a graphical formula, which facilitates entering the expression in a correct way.  It doesn't show you the step by step, but that's your part! It gives you the answer to make sure your step by step is correct. Give it a try and let me know what you think.

See more about derivatives.

Paper plates are great for counting, multiplication, basic addition and subtraction facts and for identifying quantity. All you need is a handful of paper plates and some circle type stickers or a bingo dobber.  The patterns are here and you'll also find some great strategies to help children learn many of the basics in math. Parents, homeschoolers and teachers will find these activities great! AND, the paper plates are more engaging than flash cards. Give them a try with children ages four to eight years of age.