Question

A = 33...3(2005 chữ số 3) x 33..3(2005 chữ số 3) = ?

Answer 1

Ta thấy:33x33=1089(2 c/s 3;1 c/s 1; 1 c/s8)

333x333=110889(3c/s3;2c/s1;2c/s8)

3333x3333=11108889(4c/s3;3c/s1;3c/s8)

=>333...3x333...3(2005 số 3)=111...1(2004 c/s 1)0888...8(2004 c/s 8)9

Answer 2

333...3x333...3=333...3²(2005 số 3)

Ta thấy:33²=1089(2 c/s 3;1 c/s 1; 1 c/s8)

333²=110889(3c/s3;2c/s1;2c/s8)

3333²=11108889(4c/s3;3c/s1;3c/s8)

=>333...3²(2005 số 3)=111...1(2004 c/s 1)0888...8(2004 c/s 8)9

Answer 3

i don't know