IXL | Learn grade 3 math IXL offers hundreds of grade 3 math skills to explore and learn! Not sure where to start? Go to your personalized ... Addition input/output tables - up to four digits C.17. Add two numbers up to four digits - word problems C.18. Complete the addition sentence - up to four digits C.19. Balance equations up to four digits C.20. Add three or more numbers up to four digits each C.21. Add …