Thanks all again for your tips, resources and encouragement! After 3 days break, we did the remaining problems in the worksheet and my son was giving correct solutions to all the problems. I didn't believe that my son would be able to do that after few days break but little ones disprove it all the time. This is just for the record.
Manda, you're very correct about the pattern identification. My main math goal for my son was to be able to identify patterns in math and so far I have been successful.
Latreia, several fellow BK parents have shared wonderful ideas in other threads for 2+ year old math. Some of the links are:
http://forum.brillkids.com/teaching-your-child-math/pick-just-1-program-to-teach-toddler-math/http://forum.brillkids.com/teaching-your-child-math/math-curriculum-for-toddlers/http://forum.brillkids.com/teaching-your-child-math/math-supplement-for-advanced-3-year-old-%28almost-4%29/But I will let you know what we did. Right from 4months old on, LO has been eagerly watching the Doman dot cards. He was in fact little less interested in word cards. He used to giggle, laugh and enjoy when the dot cards were shown. In the beginning, I used Doman dot cards in black. When his interest waned, I used red dot cards. When his interest waned again, I put up the equations on the wall and would show it to him daily. Likewise, we had several backup plans: powerpoint slides, powerpoint slides with his pictures, powerpoint slides with his favourite animals, etc.
I bought Little math recently because I thought he would still benefit from the dots. After about 50 lessons, he lost his interest. But I installed other languages in LM and since then he is so eager to watch the dots. Once he loses his interest in other languages, I will think of other methods.
I introduced some Montessori style math methods When he was 18months. After he turned 2, I started doing Miquon math with cuisenaire rods. This is one of the best investment in my opinion. I was also doing Marshmallow + Kitchen table style math throughout the day. Hope this helps.