Answer:
43,000: 4.3×10^4
0.0072: 7.2×10^-3
0.0000901: 9.01×10^-5
Explanation:
scientific notation: a×10^b, where should be 0<a<10
Step 1. Count the zeros
Step 2. Look at the number left, and determine whether or not it fits in the range of [a]. If not, we divide or multiply 10 to get it fit
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43,000: 4.3×10^4 (since 43 does not fit, we divide by 10 to get it fit)
0.0072: 7.2×10^-3 (since 0.72 does not fit, we multiply 10 to get it fit)
0.0000901: 9.01×10^-5 (since 0.901 does not fit, we multiply 10 to get it fit)
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