http://www-k6.thinkcentral.com/content/hsp/math/hspmath/na/common/itools_pri_9780547584973_/main.html?module=measurement&activity=11 (iTools:  Explore)

 

http://www-k6.thinkcentral.com/content/hsp/math/hspmath/na/common/mega_math_9780547585062_/megamathcd4/cm/launch.html?strActivityName=g36_1_1_I&strAssignID=1 (Buggy Bargains Level I)

 

http://www-k6.thinkcentral.com/content/hsp/math/hspmath/go_math_2012/na/gr5/amm_9780547665054_/lesson.html?g_iGrade=5&g_iChapter=90&g_iLesson=52&strUserID=st1&g_iProduct=5&g_iSection=15 (Add and Subtract Decimals)