Section 1
Answers:
- 1.6962 = 1.70 to 2 d.p.
- 0.007395 = 0.007 to 3 d.p.
- 0.4247 = 0.425 to 3 d.p.
- 0.007395 = 0.0074 to 4 d.p.
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Step-by-step explanation:
The abbreviation d.p. means decimal places
When rounding to 2 decimal places, we look at the digit in the third decimal place value slot (thousandths place). If the value is 5 or larger, then we round up. In the case of 1.6962, the second 6 tells us to round 1.69 up to 1.70
Something like 0.4247 does not round up because that second 4 is not 5 or larger. So we just are left with 0.42
The same logic applies to three decimal places, but you'll look in the fourth slot this time.
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Section 2
Answers:
- 32549 = 32500 to 3 s.f.
- 909520 =
to 3 s.f. (note the overline bar) - 32549 = 32550 to 4 s.f.
- 909520 = 909500 to 4 s.f.
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Step-by-step explanation:
Recall that for a number like 32500, the 0s are not significant. This is because we can write that as 3.25 * 10^4 to convey the same idea. The only significant figures are 3, 2 and 5.
So when rounding 32549 to 3 sig figs, we just pick on the three left most values, and the rest go to 0. The 325 does not round up to 326 because the '4' isn't 5 or larger. Put another way: 32549 is closer to 32500 than it is to 32600
When rounding 909520 to three sig figs, it turns into
. The line over the first '0' tells us that zero is significant. Without this bar, the zero would be considered not to be significant. The 9095 is closer to 9100 than it is to 9000, so that's why we rounded up.