This free math video shows the “WHY” behind the traditional subtraction algorithm normally taught in 2nd grade in the USA. Many children don’t understand what is happening in the algorithm that they are expected to memorize. Because of this, they can’t remember the steps and get confused and frustrated. Doing these types of problems with manipulative many times while also doing it on paper will help those kids who struggle as well as help those who don’t struggle with the memory task to actually understand what they are doing. You can use a Base Ten set in place of Cuisenaire Rods, but C-rods are quicker and, therefore, more enjoyable.