Thank you, Andrea, and others, for detailing for me how you use your HIG. I had a look at the HIG of a friend's and decided not to get it. I see it as another thing to take my time.
I learned math the Chinese way (I came to the US at age 31) and often come up with my own strategy. For example, ds7 is learning 5 tables.
I teach him the way I always do, maybe no one else does it this way:
for even #, 4x5 = half of 4 and then add a 0 to the end. So that is 20.
for the odd #x5, i.e. 7x5 is half of one less than the odd # 7 and add a 5 to the end. So it is half of 6 and add 5 to the end and it is 35.
For division: 20/5: cross out the 0 of the whole #, then double the first #. So 2x2=4 is the answer. If it is 75/5, then double the tens #, that is 7x2, then add 1 more. The result is 15. For 35 / 5, the it is double 3 plus 1 and the result is 7. He learned it faster this way than to memorize the table or by counting by 5s.
I think if I do one level a year, then there is time in the summer to fit in the IP. Thanks for your advice. I am getting the Standards Edition for 3A, then I don't know if I should get the IP for that since it doesn't line up well.