In the sixth grade, the math calculation is 8 minutes, and the child of 100 is not bad. It's normal speed for the first-grade children to memorize 100 questions in 8 minutes, because the requirement of dictation is 10 minutes 100 questions, so it's not bad. Oral arithmetic: while doing mental arithmetic, oral arithmetic. Oral arithmetic is to calculate with the brain and remember the results at that time with oral narration. This method is used for quick calculation, and regular practice is helpful to improve intelligence.