Прошу, нужна ваша помощь!!! С объяснением пожалуйста, завтра тест =( Умоляю!

Округлите числа с точностью до двух значащих цифр и вычислите приближённо их произведение и частное:

а) а = - 0, 0596   b = 0, 123

б) а = - 0, 493     b = - 1, 99

В прямоугольном треугольнике один из катетов равен 10, угол, лежащий напротив него, равен 30 градусов, а гипотенуза равна 20. Найдите площадь треугольника.

Подробно, пожалуйста!

По кольцевой дороге курсируют с одинаковой скоростью и равными интервалами 12 трамваев, Сколько трамваев надо добавит, чтобы интервалы между трамваями уменьшились на одну пятую

составить диалог.чтобы там разговаривали 3 человека.желательно подлиннее))

ПРОВЕРЬТЕ ОРФОГРАФИЮ. In the Russian Federation the school education is compulsory. Pupils begin to go to school at the age of six. When they complete high grades they can either continue to study at school for more 2 years, or go to a professional school where they study not only main subjects , but are able to learn some profession. When school pupils leave school they can try to continue their education in institutes or universities.
I am a pupil of the 9-th form, and now before me a choice. stay in school until grade 11, or go after the ninth. I think if I want to get a good education, I will learn up to grade 11 and then i will go to university. And after the eleventh class of possibilities is much more for self-realization.

I study a lot of subjects at school.
They are Physics, Mathematics, Biology, Russian Literature, Chemistry, English, History of this country and many other subjects.
I know that all the subjects are important and they all must be payed much attention to, but still I not like exact sciences. My favourite subjects is English. Nowadays, it's impossible to do without foreign languages because of expanding economic, cultural ties of this country with other countries of the world. Besides, one can't be a learned and well-educated person if he doesn't know at least one foreign language.

My friends support me in my choice to stay up to grade 11, because also they think that secondary education is very important nowadays . In addition, they really like my school.
My school is one of the best in town and I'm proud of it. I am very glad that I'm learning in this school.