Here is a fun game to play in class. Tell students that you want to measure something and have them tell you which units you should use as a measure for problems involving both weight and linear measure.
One of the interesting ways you can get your elementary students to work with mental math is to use visual patterns. For example, if you take all the face cards out of a set of playing cards, you’ll have the number cards remaining. Take a couple of these decks and cover up the numbers and the small designation of the suit. What you’ll have left is just the number pattern on the card. You can then use these cards as flash cards to get students to use their mental math muscles.
The goal of the activity is to have them plan a meal that meets but does not exceed the daily requirements on this chart. In order to create this meal they’ll need to use labels from the box. They can pull as few as 8 but as many as 12 labels to create their meals. They’ll need to use mental math to determine if their foods add up to or exceed the minerals allowed.
Bring in a large cylindrical glass jar that is filled with marbles of different shapes and sizes. Also bring in a tiny cylindrical glass jar that is filled with marbles. Tell the students the amount of marbles that are in the tiny jar.
Their task is to estimate the number of marbles in the large glass jar. At the end of the activity, have students count the marbles in the large glass jar and compare them to the mental math answers they came up with.
You can do this activity with your students at the board or on worksheets.
Provide them with a really long horizontal sum. Something like this:
3 + 11 + 7 + 5 + 5 + 4 + 9 + 1 + 2 + 13 + 8 =
The idea here is to group pairs of numbers into tens or multiples of ten so that they can quickly and easily find the sum using mental math.