Stage 8 - Q1 - 2 marks
Calculate.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q2 - 2 marks
Estimate by rounding each factor to 1 s.f.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q3 - 3 marks
Round to 3 significant figures.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q4 - 3 marks
Calculate.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q5 - 4 marks
A rectangle measures 24.6 m by 4.12 m. Calculate its area to 3 significant figures. Keep all digits until the last step.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q6 - 4 marks
A bag holds 145 g of 169 identical counters. Find the mean mass of a counter to 2 significant figures.
Hint
Track the place-value change before making the rounding decision.
Stage 8 - Q7 - 5 marks
Find x \(if(x\times 0.01)\div 0.1=0.72\).
Hint
Combine the two scale factors.
Stage 8 - Q8 - 5 marks
A positive integer rounds to 3600 to two significant figures. Find the smallest possible multiple of 8 that it could be.
Hint
Find the lower rounding boundary, then the next allowed multiple.
Stage 8 - Q9 - 5 marks
A pupil says that rounding to 2 decimal places and then to 1 decimal place always gives the same answer as rounding straight to 1 decimal place. Find a counterexample.
Hint
Try a number just below a 1-decimal-place halfway boundary.
Stage 8 - Q10 - 5 marks
A positive number x has exactly two decimal places. After multiplication by 0.1, it rounds to 0.35 to two decimal places. List all possible x.
Hint
Reverse the multiplication only after finding the rounding interval.