Check the following for equality and if they are equal, mention the property.
(i) (8 - 13) x 7 and 9-(13 x 7)
(ii) [(-6) - (+8)] x (−4) and (-6)- [8(−4)]
(iii)3 x [(-4) + (-10)] and [3 x (-4) + 3 x (-10)]

The product of two integers is −135. If one number is −15, Find the other integer.

An elevator descends into a mine shaft at the rate of 5 m/min. If the descent starts from 15 m above the ground level, how long will it take to reach –250 m?

If P = -15 and Q = 5 find (P-Q) + (P+Q)

An atom can contain protons which have a positive charge (+) and electrons which have a negative charge (-). When an electron and a proton pair up, they become neutral (0) and cancel the charge out. Now, Determine the net charge
(i) 5 electrons and 3 protons \(\rightarrow \) -5+ = -2 that is electrons ⊝⊝
(ii) 6 Protons and 6 electrons \(\rightarrow \) 
(iii) 9 protons and 12 electrons \(\rightarrow \)
(iv) 4 protons and 8 electrons \(\rightarrow \)
(v) 7 protons and 6 electrons \(\rightarrow \)