Improving Your Mental Math

Feb 4, 2021 | Brampton South

Mental math can be difficult for students because they are trying to keep track of many steps in their mind without writing anything down. I recall my teachers asking us to practice mental math, and dreading it because it was tiring. However, these are some tips that can help students break down the questions!


  1. Finding Half

    1. For two digit numbers, it is easier to break down the number into the tens place and the ones place, take half of each, and add it together. For example: Half of 29 = Half of 20 + Half of 9. Therefore half of 29 = 10 + 4 ½ = 14 ½.

    2. The same can be done for three digit numbers. Half of 375 = half of 300 + half of 70 + half of 5. Therefore half of 375 = 150 + 35 + 2 ½ = 187 ½. 

      1. Hint: if a student is not sure what half of 300 is, ask them if they know half of 30 first!

  2. Single digit addition

    1. For these questions, have students try to make 10 first! For example, when asked 7 + 5, ask them 7 + ? = 10? 

  1. Another key to getting faster at answering these questions is to verbally practice these addition facts with your child. With continued practice, it will come automatically to them. In grade 2, my teacher used to have us try to answer a whole page of addition questions in less than 1 minute. If we got them all correct, we could choose a prize from her prize box!

  2. The same applies to multiplication! Practice practice practice will help students improve. 

  1. Multiplying multi-digit numbers by a single digit

    1. Again break it down and multiply each part by the single digit.

    2. For example, 23 x 9 can be broken into (20x9) + (3x9) = 180 + 27 = 207!


I suggest that when you first try showing your child these methods, to write it down from them first so they can see how the steps come together! 


-Cianna Choo