Stage 8 - Q1 - 2 marks
Multiply.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q2 - 2 marks
Multiply.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q3 - 3 marks
Multiply.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q4 - 3 marks
Multiply.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q5 - 4 marks
A rectangle measures 5.5 m by 0.6 m. Find its area exactly.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q6 - 4 marks
A rectangle measures 6.6 m by 0.8 m. Find its area exactly.
Hint
Use a related integer multiplication, then account for the scale factor.
Stage 8 - Q7 - 5 marks
Use \(24\times 35=840\) to find \(2.4\times 0.35\) and \(0.24\times 3.5\) without another long multiplication. Explain why the results agree.
Hint
Track the total scaling of both factors.
Stage 8 - Q8 - 5 marks
A pupil says \(0.6\times 0.7=4.2\). Give two independent checks showing the error, then correct it.
Hint
Use both size reasoning and place-value scaling.
Stage 8 - Q9 - 5 marks
A rectangle has area 4.32 \(\text{m}^{2}\) and one side 1.8 m. Find the other side, then determine how the area changes if both sides are multiplied by 0.5.
Hint
Two dimensions each contribute a scale factor.
Stage 8 - Q10 - 5 marks
Two positive numbers each have one decimal place and sum to 2.0. Find the greatest possible product and explain why no other pair is better.
Hint
Compare pairs at equal distances on either side of 1.0.