IDEA

Both UDL and AT address the approach of learner variability in that they both address the individual learning needs of students.
The method in which they address these needs is different.  UDL is a dedicated strategy that addresses numerous areas of curriculum development. AT allows individual students to conquer those barriers presented by curricular tasks. 
UDL is a set of principles that models curriculum development  resulting in equal opportunities for learning. It targets on instructional goals, methods, materials, and assessments that can be adequately assessed and used by all students, disregarding of ability or background.  UDL is a malleable approach that may be accommodated  to meet individual needs. 
"AT devices and services are delivered re-actively after a referral and evaluation of an individual student. UDL is given to everyone with the understanding that those who need specialized support will use the tools when they need them"(Illinois Assistive Technology Guidance Manual).

In CAST UDL Exchange, I found an amazing math site. This is a math website that involves games lessons, quizzes, brain teasers and manipulative s. Its called cool math for kids and its for children from KG to 6th grade. This lesson engages in diverse learners by helping them play in groups and verse each other to see who knows the math problems. Its about math and math is universal so everyone of all backgrounds can understand it and is easy to teach. The technology tools being used is a computer website/ games. The purposes this technology tool can serve would be helping children collaborate with one another as well getting engaged into the math subjects being learned and succeed in them. 

 Monster Math is a game for kindergarten to 5^th grade students to practice Common Core math skills.  On either iPhones, or iPads, students complete math problems in order to progress through the game’s storyline. Although all students follow the same storyline throughout the game, the games allows players to customize which skills they would like to focus on.  Monster Math offers both a free and pain version of its app. 
another math app I have discovered is monster math located on the app store.