Not sure about expaned form. In expanded form it can have a maximum of six. Some people do not include addends whose value is zero.
Thus, 120456 can be written as
1*105 + 2*104 + 0*103 + 4*102 + 5*101 + 6*100
or
1*105 + 2*104 + 4*102 + 5*101 + 6*100.
Expaned form
yes.
log17.0002
Any two digit number in which: (a) the units digit is not 0, and (b) the two digits are different will form a new 2-digit number when the digits are interchanged.
700+1+4
20.0+3.0+0.005
40+4+0.8+0.01+0.005
157 is already prime. No factorization.
600+2 IS the expanded form! The regular form is 602.
Six of them.
12
Every square of a 4 digit number has more than four digits.