Current location - Training Enrollment Network - Mathematics courses - How to calculate the addition and subtraction within 20 in the first grade mathematics?
How to calculate the addition and subtraction within 20 in the first grade mathematics?
Today, my mother gave me a question 3ⅹ3=? I snickered to myself, thinking that my mother had studied for so many years before! I can't believe I asked such a childish question. So I answered absently: "3ⅹ3=9." Mom asked me 33ⅹ33=? I did some calculations on the draft paper with a pen, and I got 1089. I will answer immediately.

Then my mother asked 333ⅹ333=? I got 1 10889 after a stroke of calculation, so I answered my mother's question again. Mom seemed dissatisfied and asked 3333ⅹ3333=? I suddenly froze. This is because my mother stopped asking, but asked me if I found any patterns. I read every answer carefully and finally understood. It turns out that each number is 9, ten numbers are 8, and the highest number is 1. Each occurrence of 1 3, 1 and 8 in the two factors increases by 1 respectively. I immediately got 1 1 108889 from here. We also know that we can use this law to solve many problems. I immediately told my mother about this rule, and a bright smile appeared on my face.

At this time, I deeply realized that "nothing is difficult in the world, nothing is impossible to a willing mind". This realizes that as long as we observe carefully, nothing will baffle us.