How do I get an answer right without writing it down with pencil or paper?

28 29 42=99 is it communtative or associative

What is 15 litres in gallons

5% converted into a decimal

Mr Jenkins bought the same number of blue pencils as green pencils. Blue pencils come in packs of 5, and green pencils come in packs of 4. What is the least number of blue or green pencils Mr Jenkins could have bought.

The plot has an area of 78,125 square meters and is 125 meters wide. What is the length of the plot?

Solve. A recent advertisement claimed that 2 out of every 5 doctors recommend a certain herbal supplement to increase energy levels.

What is 4 divided by 230

Over a period of five days, the average time of a commuter train trip from one town to the city was 77 minutes. One trip was 71 minutes, another was 74, and two each were 78 minutes. How many minutes long was the fifth trip?

A 4 pound package of peanuts is divided into 1/4 pound packages. How many 1/4 pound packages will there be?

An item sells two for 66. what should 5 items