Place Value and Multi digit Addition and Subtraction
In unit 1, your child will use place value drawings and chart to help understand that the place value of each place is 10 times greater than the value of the digit to the right of its place. Below are two strategies that we will use in solving multi-digit addition.
In subtraction, students often make the mistake of subtracting in the wrong direction. Students may think they always subtract the smaller digit from the larger digit, but this is not true. To help students avoid this error, our math program encourages students to "fix" numbers first then subtract.
When one or more digits in the top number are smaller than the corresponding digits in the bottom row, fix the numbers by "ungrouping". For example 1,634 - 158 is shown below.
When one or more digits in the top number are smaller than the corresponding digits in the bottom row, fix the numbers by "ungrouping". For example 1,634 - 158 is shown below.
In the method above, the numbers are ungrouped from right to left, but students can also ungroup from left to right. Students can choose whichever way works best for them.