15 + 65  $\div$  5 - 39

(a)  

20  $\div$ 4 (5 - 2) 

(a)  

(2 $\sqrt{2}$  + $\sqrt{18}$  - 6 $\sqrt{50}$   ) $\times\sqrt{2}$  

(a)  

 $\left(60-20\right)^2$  -  $\sqrt{1,600}$  + 98  $\div2$  

(a)  

 $\frac{45}{100}+78\ -\ 43+0.55$  

(a)  

850 - 790 +125 +79 - 6

(a)  

 $\left(100^2-99^2\right)\times20$  

(a)  

 $\left(7\sqrt{5}\times2\sqrt{5}\div14\right)-21$  

(a)  

 $\frac{8\sqrt{81}}{3}\times\frac{2\sqrt{144}}{6}-61$  

(a)  

 $9-13\times6+7$  

(a)  

 $\frac{43}{6}-\frac{216}{24}+\frac{7}{3}$  

(a)  

 $0.119+65.881-12\times4\div3$  

(a)  

 $\frac{1}{3}+\frac{11}{3}-18\div2$  

(a)  

 $0.9897\times10^4+77-98$  

(a)  

 $1-1\times2+1$  

(a)  

 $8\times\frac{9}{4}-8\sqrt{64}$  

(a)  

 $250\div5-2\sqrt{625}$  

(a)  

(a)  

(a)