Can U Solve This???

9,4,6, ?,10,20

This a number pattern qns. heard that it is a pri 2 exam question.
my boss gif it to me and let me try... ok.. i try it even though i hate number pattern.
After trying for 15 mins, i gif up... got no time to think and also mental block....

found out the ans and the reason... but lata found out there is another ans...
veri veri tricky....

faster gif it a try and tell me ans...

hahahhaha

Welcome Jordon Goh

hahaha... today got a very very very cute little bady boy come to this world... and he is Jordon Goh.. so cute... so small & tiny ... also veri handsome. so happy for my aunty n yi zhang... he dame to this world just 2 mins past 12am.. i think shld be the 1st baby for todae.... so cute...
Hope he is always healthy....

Welcome to this World Jordon Goh!!!