## Thursday, October 24, 2013

### MaTh activity Thursday: 3.NBT.A.2 (Adding/subtracting up to 1000)

It has been an extremely busy week here at my house.  I might only be able to post once a week and occasionally twice a week.

Anyway, for this MaTh edition I will be focusing on CCSS 3.NBT.A.2!
This standard expects 3rd graders to: Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

So, let's take these two methods, knowing strategies and knowing algorithms.

A strategy is defined as a plan of action or policy designed to achieve a major or overall aim.  So to me, knowing strategies is like knowing shortcuts and all the rules behind how to work on a problem to get the answer.

Algorithm is defined as a process or set of rules to be followed in calculations or other problem-solving operations.  This is knowing the steps to be taken (like regrouping).

It is important for children to have both strategies and algorithms.  If kids only know the algorithms and not the concepts or strategies math will become difficult.

So here are some past posts that can help kids understand place value to help them add and subtract.
When a child sees 634 + 342 or the reverse 634 - 342 you should discuss ways to solve it.  Do they automatically go to the set rules they have been taught or do they do some of it in their mind.  Have the children explain how they got their answers.  Children fluent in math skills will know more than one way to do the problem and will probably know which way is the easiest for the particular problem. : )

I recommend if children struggle with this reinforce two digit numbers and even one digit numbers and make sure they understand the place values by understanding quantities with those values.

What ideas or math activities do you have to share?