The Real Number System - SS1 Mathematics Past Questions and Answers - page 1

(i) $6\times (2+3^2)-4=6\times (2+9)-4$

= $6\times 11-4$

= $66-4$

= $62$

(ii) $(18÷2of\frac{1}{4})\times (\frac{2}{3}÷\frac{3}{4}\times \frac{5}{8})÷(\frac{2}{3}÷\frac{3}{4}of\frac{3}{4})=\left(9of\frac{1}{4}\right)\times (\frac{2}{3}÷\frac{3}{4}\times \frac{5}{8})÷(\frac{2}{3}÷\frac{3}{4}of\frac{3}{4})$

= $(\frac{9}{1}\times \frac{1}{4})\times (\frac{2}{3}÷\frac{15}{32})÷(\frac{2}{3}÷\frac{9}{16})$

= $\frac{9}{4}\times (\frac{2}{3}\times \frac{32}{15})÷(\frac{2}{3}\times \frac{16}{9})$

= $\frac{9}{4}\times \frac{64}{45}÷\frac{32}{27}$

= $\frac{9}{4}\times \frac{64}{45}\times \frac{27}{32}=\frac{9}{4}\times \frac{64}{15}\times \frac{9}{32}=\frac{9}{4}\times \frac{2}{15}\times \frac{9}{1}$

= $\frac{3}{2}\times \frac{1}{5}\times \frac{9}{1}=\frac{27}{10}=2\frac{7}{10}$

Users' Answers & Comments

(i) $+12-14+10=-(14-12)+10=-2+10=+(10-2)=+8$

(ii) $-11-12+3=-(11+12)+3=-23+3=-(23-3)=-20$

Users' Answers & Comments

(i) $-28÷-3\frac{1}{2}=-\frac{28}{1}÷-\frac{7}{2}=-\frac{28}{1}\times -\frac{2}{7}=+(\frac{28}{1}\times \frac{2}{7})=+\frac{8}{1}=+8$

 

(ii) $9\times -4\frac{1}{2}=\frac{9}{1}\times -\frac{9}{2}=-\frac{81}{2}=-40\frac{1}{2}$

 

(iii) $-63\times -6=+(63\times 6)=+378$

Users' Answers & Comments

2	70		2	120
5	35	2	60
7	7	2	30
	1	3	15
		5	5
			1

Thus, $70=2\times 5\times 7$,

$120=2\times 2\times 2\times 3\times 5$

Common factors are one set of $2$ and $5$.

Hence, the Highest Common Factor = $2\times 5=10$

Users' Answers & Comments

2	108	150
2	54	75
3	27	75
3	9	25
3	3	25
5	1	25
5	1	5
	1	1

The Lowest Common Multiple is thus, $2\times 2\times 3\times 3\times 3\times 5\times 5=2,700$

Users' Answers & Comments