1) Introduce new lessons.
Hello students, you are about to start a pleasant journey of mathematical exploration, please listen to a paragraph before class**. Well, a lot of classmates sang along, what do we all have to eat on our birthdays?Yes, cakes. Now please look at the big screen, Mom divided Peppa's birthday cake into 8 pieces equally, Dad ate 3 pieces, Mom ate 1 piece, so how many cakes did Dad and Mom eat in total?3/8+1/8=?How do you calculate the result?
The teacher saw that everyone frowned, it doesn't matter, today we will learn Xi "Addition and Subtraction of Fractions with the Same Denominator".
2) New knowledge**.
Now please take out the learning tools in the school tool bag, fold them independently, paint them, count them, and then discuss them in groups of four people: how to calculate the addition and subtraction of fractions with the same denominator
Later, the teacher asked the group representatives to report on your wisdom. The discussion among the students is gradually quieting down, please send a representative to the third group with the most neat hands to answer. Okay, sit down, your group is really hands-on. They replaced the cake with round pieces of paper, divided the round pieces of paper into 8 equal parts, painted 3 of them in blue to indicate that Dad ate 3 cakes, and one of them painted red to indicate that Mom ate 1 piece of cake, and found that Dad and Mom ate a total of 4 8 cakes by counting.
The male classmates in the last row of the first group, you seem to have something to add, please speak. Well, please sit down, your group is a small discoverer, and not only by coloring but also by coloring the result is 4 8, but by folding it, it is exactly 1 2, so the final result should be 1 2. Are there any other groups that disagree?Please say that the first female student in the fourth group with the most active hand is that you divide the round piece of paper into 8 equal parts, and cut it out, and find that 3 8 + 1 8 = 3 1 8 + 1 1 8 = (3 + 1) 8 = 4 8, and the result after simplification is also 1 2, your group's idea is really unique, and the teacher gives you a thumbs up. So 3 8+1 8=(3+1) 8=4 8=1 2 Now ask the students to observe this equation and tell the teacher aloud how to calculate the addition of fractions with the denominatorWell, very good, add the fraction with the denominator, the denominator remains the same, add and subtract the numerator, and the calculation result should be reduced to the simplest fraction.
The teacher also had a question, how to calculate how much cake Dad ate more than MomPlease list the equation independently and then cooperate with your tablemates**How to calculate the result. Okay, it's time, the fourth male student by the window on the left, you are sitting in the most upright posture, please answer. Not only did you answer correctly, but you also analyzed the truth, so please take a seat. Combining the hands-on operation with the content you just learned and Xi the addition and subtraction of integers, you found that 3 8-1 8=3 1 8-1 1 8=(3-1) 8=2 8 simplification yields the result 1 4, do you all agree?The teacher saw that most of the students nodded, and asked the students to carefully observe these two equations, so how to calculate the addition and subtraction of fractions with the same denominatorYes, the fraction with the same denominator is added and subtracted, the denominator remains unchanged, the numerator is added and subtracted, and the final result is reduced to the simplest fraction.
3) Consolidation of Xi.
Have you mastered it?The teacher is now going to test everyone, the whole class of the fourth grade 2 class on Children's Day participated in the performance, and half of the students participated in the dance, of which there were 3 10 male students who danced, and the male students who did not dance all participated in the singing, and the female students of 3 10 participated in the singing, how many male students participated in the singing?How many female classmates are dancing?Host: The students in Class 3 of the fourth grade are very artistically talented, and they can either sing or dance, is it correct?The teacher sees that the students have stopped writing, please look at the big screen, you have done it right, check and correct each other at the same table, and give applause to the correct table.
4) Summary of homework.
This lesson is coming to an end, please talk about what you have learned through this lesson Xi you have learned in the group**Do you need to keep refueling?Well, the teacher heard the classmates talking very intensely, mathematics is also applied to life in life, as long as you have a pair of eyes that are good at discovery, mathematics is all around us.
After class, please ask your classmates to put more ** on the first.
The first and second questions are written in the practice book, and interested students can adjust the Xi of the Xi on the multi-**.
After class, goodbye, classmates.