Mental math – more needed?

This discussion is part of a collection:Developing Fact Fluency

re: Mental Math Strategies
Shouldn't this be an every day component of math lessons? This resource 'Mental Math Strategies' at ML is a good starter set for daily mental drills. What other mental drills could add to the variety needed to keep the routine fresh? Is it still needed at 5th gr and middle levels?

Groups:

Replies

There is a great resource from Mathwire that was just entered in this catalog called "Activte Participation: Using Math Templates"; it includes information on using math templates in the classroom during "drill" type activities or as exit tickets. While it is not "mental math" it does teach students to pull from their resources and use the appropriate template. If used correctly students may even choose to use these on their own to complete classwork.

Thanks, Beth. Templates can help reveal patterns that foster mental calculation, e.g., what happens to the units digit when you add (subrtract) 8 or 9. Another pattern I think gets overlooked is counting up or down by five.

Column addition is another vehicle. Someone showed me a trick when I was a kid. Take two digits at a time adding down a long column of 1-, 2- or 3-digit numbers. Many times you'll be adding 9, 10 or 11 to your running total.

When students (gr. 3 and up?) have to use a calculator or a pencil to get 25 – 9, they need more work on number sense. Here's a game. Teacher writes three digits on the board, say 2, 3, 8. A student responds, "I can make 36." If no challenger responds with a correct method (38 – 2), in 15 seconds say, then the first student explains and earns a point, and the next student in rotation offers a different result. If the challenger is successful then they call out the next result. Play for 5 minutes and keep scores for a week. The weekly winner gets ...? (To the front of the lunch line, oh yeah!).

Having taught both 5th and 6th grade, I would say that mental math is still necessary at this level. Often during lessons I would do mental math problems with the students as a routine breaker. The students would get up out of their seats and use dry erase boards to write their response to problems from the IWB, I would give them 30 seconds - 1 minute for each problem. Some students would still insist on writing out their thinking, but it wasn't necessary.

I agree that using the dry erase boards is great for showing answers! Sometimes with 3rd or 4th grade students I use problems whose answers are between 0 and 10 so we can use fingers to display answers. That way we can do a quick mental math problem anytime with no need for any type of equipment.

Response clickers are great for this too! The kids love using them and they give immediate feedback (without the kids comparing answers). I would definitely advise trying to use these at least once a month if there is only one set in your school, but more often for quick assessment and drill if you have ready access to them.

Using the response clickers is a great idea. Thank you so much for suggesting it.