MULTIPLICATION OF NUMBERS CLOSE TO10^3(=1000)

This method is very easy when compared with general multiplication, but useful only when the numbers are close to powers of 10.

Ex 1) 998x987

• here 998 is 2 less than 1000& 987 is 13 less than 1000.
• multiply 2&13. And write it as 026
• now take 998-13 or987-2 which is equal to 985 (cross subtraction)
  

• therefore 998x987=985026

998........2
X 987........13
--------------------
985 026
here 985=998-13 or 987-2(cross subtraction)
026=2X13
Therefore 998x987= 985026

Ex:2) 1007x1013

• here 1007 is 7 more than 1000&1013 is 13 more than 1000
• multiply 7&13 and write it as 091
• now take 1007+13 or 1013+7 (cross addition) which is equal to1020.
• therefore 1007x1013=1020091

1007................7
X 1013..............13
---------------------------------
1020 091

Therefore 1007X1013 =1020091