I teach the upper grades in my school, yet I continue to see kids who do not even have basic algebra skills in place. As a parent, I'm very aware of what my own children are learning in school. For the most part, I've been happy with their progress, but as they rise in grade level, I'm starting to see more emphasis on a loose understanding of the concepts and less emphasis on skills__particularly skills with arithmetic of fractions. The main problem with what I see with my students and my own children is that kids are taught "concepts" and are not taught skills__unless they're lucky enough to have a teacher who knows better. Most particularly, children are not taught mastery of arithmetic with fractions. Unfortunately, virtually all of their future math education depends on being able to do fractional arithmetic.
Math worksheets don't provide immediate feedback _ Most teachers are familiar with the long delay between when students complete a worksheet, and when they get their correct page. Most don't get anything back until the next day or the next week. In the meantime, the students continue to practice incorrectly. It's no surprise that immediate feedback has been shown to increase student performance and diligence. Unfortunately, math worksheets have no mechanism for keeping a student from moving to the next problem until after they demonstrate understanding. Good curriculum software can address this issue by giving students instant responses and strategic feedback. The use of visual cues and auditory feedback helps students quickly recognize their fraction errors and self_correct. This just_in_time feedback system eliminates practicing incorrectly, while promoting self_correction and independence.