Express each of the following in standard form:
(i) 345
(ii) 180000
(iii) 0.000003
(iv) 0.000027
(i) 345 = 3.45 × 100 = 3.45 × 102
(ii) 180000 = 18 × 1000 = 18 × 104 = 1.8 × 10 × 104 =1.8 × 10(1+4) =1.8 × 105
(iii) 0.000003 = 
= 3 × 10-6
(iv) 0.000027 = 
= 2.7 × 10(1-6) = 2.7 × 10-5
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