Algorithms are very useful in mathematics.
What the TERC curriculum doesn't support is the rote teaching of a single algorithm for each operation. For example, there is a great deal of research on how students naturally add tens first, then ones, when they have a good foundation in place value and the properties of addition. However, it has the advantage of focusing attention on the largest part of the number first, leading immediately to a sense of what a reasonable answer should be. Adding starting with the largest place is a mathematically sound, generalizable algorithm that many adults use. The curriculum supports efficient, accurate, and flexible use of algorithms that are well understood by the user.