Question

(1423)5×(110011)2-(243)5

Answer 1

(1423)5*(110011)2-243*5=

10*1423*110011-1215=

14230*11*10001-1215= (To multiply by 11, write down the first and last digits then add each digit to its neighbour: 1(1+4)(4+2)(2+3)(3+0)0=156530)

156530*10001-1215= (To multiply by 10001 add 4 0's to the end of the number then add the original number. It's easy to do this because the last 5 digits of the number are just written as the last 5 digits of the result and only two digits (3 and 1=4) are needed to be added, so 15653.... becomes 156545630.)

1565300000+156530-1215=

1565456530-1215=

1565455315