1. Master the operation order of fractional elementary arithmetic and calculate it correctly.

2. Cultivate the study habit of carefully examining questions, calculating and checking.

(B) Teaching focus and difficulties

1, the key point: master the operation order and method of fractional elementary arithmetic, and be able to perform four operations correctly.

2. Difficulties: Master the operation order and method of fractional elementary arithmetic, and be able to correctly calculate four.

(3) Teaching activities

Activity content Organization and implementation of activities

Time allocation of design intent (including teacher activities and student activities)

Basic exercise 1, showing oral math problems, (completed within the specified time)

1/2+ 1/3 3/4- 1/2 2/5×2 4/7÷2

1/5÷ 1/ 10 1/3÷ 1/5 1- 1/4 3÷ 1/3

1/6+24× 4/51/5+1/23-1/3 Improve students' verbal and quick calculation ability for 5 minutes.

1. Show the questions to be exchanged and summarize: (exchange the experience of previewing)

A, fractional elementary arithmetic operation order and integer elementary arithmetic operation order ().

B, recall what is the order of integer elementary arithmetic operations?

2. Report in groups.

3. Teacher's summary. Strengthen the ability of autonomous learning from preview, and provide activity space for displaying preview results in groups.

Explore new knowledge 1, pre-class evaluation: directly show quiz questions, and students can complete them independently.

1/5+5/6×3/5 [ 1-( 1/4+3/8)]÷ 1/4

1/5÷[(2/3+ 1/5)× 1/ 13]

2. Students exchange and correct, asking students to show the calculation process on the blackboard because this part of knowledge is evaluated on the basis of existing knowledge and experience, with the purpose of checking students' ability to examine questions and calculate. 23 minutes

3, statistical accuracy, and then focus on the explanation.

4. The teacher summed it up. Help students to further straighten out the operation order (especially students with learning difficulties)

Consolidation exercise 1, calculation:

20- 1/4×2/5 [4-(3/4-3/8)]×4/29

(7/8-5/ 16) × (5/9+2/3) Consolidating what students have learned and designing an open exercise can give full play to students' autonomy and creativity. 17 minutes

2, column calculation:

What's the difference between 2/3 plus 1/5 and 1/6?

The difference between 4/5 and 2/3 is multiplied by a number, which is equal to 2/7. What's this number?

3. Use four numbers (1/2, 2/3, 3/5, 4/9) to make three-step calculation, and then calculate the results.