SCM math book 2: How to use tables for addition and subtraction?

I am happy to help! First, I need to tell you that my memory failed me. When I answered you before regarding the tables, I thought that the student wrote addition tables in the math notebook as she will when she does the multiplication tables (see page 199 of Book 2 for the first multiplication table).

Yes, your daughter can look at the tables and find the corresponding row to answer questions for as long as she needs to. She may find it helpful to make each table in her math notebook as the tip at the bottom of page 25 describes. For subtraction problems, she has the visual of the 2 pennies and the 5 pennies together being 7 pennies. So she would think, while looking at her table, 7 pennies is 2 pennies plus 5 pennies, so 7 pennies minus 5 pennies is 2 pennies.

She could also write tables similar to the multiplication ones (see page 199) in her math notebook if that would be helpful to her. It may help her see the subtraction complement of addition better. To build an addition table similar to the multiplication ones, have her write the number for the table she is working on in her normal size handwriting. Then have her write the number being added to that number in smaller handwriting above it. The answer goes under the number for the table being worked on. Each number should be in its own square in the math notebook. For example, let’s say she is working on the 2’s table. She would write the number 2 in one square in her math notebook, then write a small number zero in the square above the 2. Finally, she would write the answer of 2 in the square under the first 2. She would continue writing the table in this way through 2 + 10. In the end she would end up with what looks like vertical equations without the symbols for addition and equals.

For an addition problem, she would then look at her table for a particular number and find the small number being added to that table’s number to find the answer. Subtraction is mostly the reverse so she would find the number she is subtracting from in the answer portion of the table, then the answer is whichever of the two numbers is not being subtracted. For example, if she is solving What is 7 minus 2, then she would find the number 7 as an answer in her 2’s table. Working the equation backwards, she would start at the 7, she subtracts 2, so the answer is the 5 above the 2. If she is solving What is 7 minus 5, then she will do the same procedure but this time she should see the 5 above the 2 in the equation in the table and know that 2 + 5 = 7 so 7 – 5 = 2. (I hope that makes sense. It’s hard to describe in writing.) She can use whichever table set up works best for her for as long as she needs them. As she uses the tables over and over again, she will memorize them.

The purpose of the tables is to give a visual concrete table for the student to discover patterns on her own. It also gives a less cumbersome way to use concrete objects than the usual use of manipulatives when the work focuses on a particular table.

For your specific example of her struggling with the word “from” for subtraction, try guiding her to discover what is wrong with her equation. “Read your equation to me. Does anything seem odd to you about that?” Give her time to think about it. If she can’t figure it out, then have her use manipulatives (beads, M & Ms, crackers, Legos, or any other object) to do the problem. Read it to her again, explaining that “from” is her cue that this is a subtraction problem. Have her get the appropriate number of manipulatives and see if she can solve it that way.

Remember your role in teaching her math is to guide her discovery, encourage her in her ability, give her time to think and ponder what she needs to do to solve an equation, and support her when she needs a bit more help.