Answer:
a) 300000
b) £200
c) 20000 km
Step-by-step explanation:
You always start counting significant digits starting with the left-most non-zero digit in the number. If there is no decimal point, the right-most non-zero digit is the last of the significant digits. If there is a decimal point, the right-most digit is the last of the significant digits.
The number 276040 in part (a) has 5 significant digits: 2, 7, 6, 0, 4.
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We want numbers with only 1 significant digit. That means we keep only the left-most non-zero digit, rounding up if necessary.
a) 276040 ⇒ 300000
b) £238.02 ⇒ £200
c) 17521 km ⇒ 20000 km
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Additional comment
In part (b), we dropped the decimal point and the fractional part because we want the count of significant digits to stop with the first one.
