16 ÷ (2 + 6) + 18[3 + (4 × 6) − 21]
(6.67*10^-11*6*10^24*2)/(6.4*10^6)^2
(4.259 x 10^26) / (3.9 x 10^25)
7/8 + 1/6 divided by 2/9
3.9 x 10^25/4.259 x 10^26
(10^6)^2
(-19/5)x(41x(-5/19))
a^2-a
a-a^2
((3a)/(ax+ay))+((2a)/(ax+ay))