Mental math is a students ability to make calculations in their mind without the guidance of pencil and paper, calculators, or other aids. It is often used as a way to calculate and estimate quickly, using math facts that students have committed to memory, such as multiplication, division, doubles facts, etc.
Therefore, to develop as a mental math whiz, students must have a strong number sense.
In the early years, subitizing activities are extremely useful to lay the foundations of students developing a strong number sense. This early maths skill encourages children to rapidly recognize quantities. These subitizing flash cards, used daily, are a great way to improve your students skills.
This first set of flash cards is simply black dots – ask your students to quickly tell you how many dots they see on each flashcard.
This second set of flash cards has some black dots and some white.
Ask your students to tell you how many black dots, how many white dots and then how many dots altogether?
Finally, some of these colored subitizing flash cards have three different colors, this is a good extension for those students who have well developed subitizing skills.
Teaching Number Facts & Mental Math Strategies
As children learn to add numbers, they become very reliant on counting. This is OK with small numbers, however, it can cause difficulties down the road when students begin to add larger numbers mentally. For example, if a student used counting strategies, such as counting on by ones or using tally marks, to add 35 + 45, they would most likely loose count. It is also not an efficient way to work out this sum. Therefore, embedding basic number fact and place value knowledge in students is another important step in the process of being able to solve math problems mentally.
A knowledge of number facts then transforms into the different mental strategies that can be used. We have a variety of posters and resources that can help in this part of the teaching process:
Encourage ‘number talks‘ daily! Students discussing their strategies is imperative in teaching mental math.
Every morning in my classroom, we had ‘number talks’. I would put a couple of math problems on the board and students would work out each problem in their head. Once they had an answer they would place their hands on their head.
They discussed their answer and selected a strategy with a partner and then with the class. The discussions that took place were some of the best teaching moments I had that year! Seeing the ‘lightbulb’ light up in students heads as they heard their friends explain to them how they had worked it out!
Practice, Practice, Practice
Along with the explicit teaching and discussing of different strategies, it is also important to provide a number of other hands-on opportunities for students to cement different strategies. Here are some of my favorite:
101 and out!
Kids love playing this! Especially if they play it against their teacher!
Explain to the class that initially they will be playing against you, then against each other. The aim of the game is to get to 100 without going over!
Each team rolls a dice (or two). They then decide if they are going to use the total as a place value of tens or ones/units. For example, if they roll a 6 they can choose to add 6 to their total or 60. Each team needs to then record their running total on a sheet of paper and color the different sub totals on their hundreds board.
Bingo is always a very popular game to play in the classroom. We have a variety of multiplication, division, addition, and subtraction bingo games available. These can assist in cementing certain math facts in your students.
A game using addition, subtraction, multiplication, and division.
The aim of the game is to cover each of the numbered boxes on the game card by correctly answering the calculation that has been drawn out.
Use whichever combination of operation cards to adjust the difficulty of the game.
Move Up the Ladder
Race against the clock!
Kids always love a bit of a challenge. Using our Number Ladder template, students must roll two dice and then add the numbers together as they ‘climb’ the ladder.
Who can climb their ladder the quickest?
Laminate the ladder and use a white board marker so that it can be played again and again!
Create Mental Math Flip Books
Using our addition flashcards, create an addition flip book. A quick and easy resource that can be used all year round. I used to set the timer for 5 minutes and get the students to write the answer (the answer only) of as many sums as they can. Who got the most correct?