question_answer 6)

Express the following as cm using decimals. (a) 2 mm (b) 30 mm (c) 116 mm (d) 4 cm 2 mm (e) 162 mm (f) 83 mm TIPS As we know that, \[+5\times \frac{1}{100}\] To convert mm into cm, we use tenths i.e. multiply given mm by 1/10 cm.

Answer:

(a) We know that, \[+50\times \frac{1}{100}\] \[+7\times \frac{1}{100}\] \[+75\times \frac{1}{100}\] (b) We know that, \[10mm=1cm\Rightarrow 1mm=\frac{1}{10}cm\] \[\therefore \] \[4mm=4\times \frac{1}{4}cm=\frac{4}{10}cm=0.4cm\] (c) We know that, \[10mm-1cm\Rightarrow 1mm=\frac{1}{10}cm\] \[\therefore \] \[7cm5mm=7cm+5mm\] \[=7cm+5\times \frac{1}{10}cm\] \[\left[ \because 1mm=\frac{1}{10}cm \right]\] (d) We know that, \[=7cm+\frac{5}{10}cm=\left( 7+\frac{5}{10} \right)cm\] \[=(7+0.5)cm=7.5cm\] \[1000m\Rightarrow 1km\] \[\Rightarrow \] \[1m=\frac{1}{1000}km\] (e) We know that, \[\therefore \] \[52m=52\times \frac{1}{1000}km=\frac{52}{1000}km=0.052km\] \[1m=\frac{1}{1000}km\] \[\therefore \] (f) We know that,\[340m=340\times \frac{1}{1000}km=\frac{340}{1000}km=0.340km\] \[1m=\frac{1}{1000}km\]\[\therefore \] \[2008m=2008\frac{1}{1000}km=\frac{2008}{1000}km=2.008km\]