Trick to square number b/w 40 and 49

Trick to square number b/w 40 and 49

43^2=?? (calculate in 2 or 3 seconds)
STEP 1: Subtract the number from 50:
50-43=7
STEP 2: Now subtract the calculated result from 25:
25-7=18
STEP 3: Square the result from step 1(make it 2 digit number_ _)
7^2=49 ( it's 2 digit number) 
STEP 4: Then place result of step 3 after result of step 1:
18 and 49=1849


46^2=?? (calculate in 2 or 3 seconds)
STEP 1: Subtract the number from 50:
50-46=04
STEP 2: Now subtract the calculated result from 25:
25-04=21
STEP 3: Square the result from step 1(make it 2 digit number_ _)
04^2=16 ( it's 2 digit number) 
STEP 4: Then place result of step 3 after result of step 1:
21 and 16=2116


48^2=?? (calculate in 2 or 3 seconds)
STEP 1: Subtract the number from 50:
50-48=02
STEP 2: Now subtract the calculated result from 25:
25-02=23
STEP 3: Square the result from step 1(make it 2 digit number_ _)
02^2=04 ( it's 2 digit number) 
STEP 4: Then place result of step 3 after result of step 1:
23 and 04=2304