The right angle is 90 degree.
The weather is so cold, especially in January.
Can you calculate 3 times 19?
She must have a smart brain.
May I see a part of you homework?
He can say four kinds of languages.
I nearly slept at 1 am yesterday.
My computer system is broken.
People invent things every day.
You can develop your marks through reading.
Einstein had many inventions in his life.
I don't know how to use abacus.
Are you sure you have an accurate answer?
The electronic instruments help us a lot in our life.
Calculators are convienent.
What is 9 subtract 3?
2 multiply by 3 equals 6.
The percentage of population increases every year.
What is the square root of 16?