Math 2 Lesson: Numbers
1.1. Knowledge to remember
– Know the position and name of terms and sums in an addition.
– Perform addition without memory within 100 and apply it to solving puzzles
Attention: 35 + 24 is also called the sum.
1.2. Math forms
Type 1: Perform the calculation.
– Set in vertical columns, numbers in the same row are placed straight together.
– Add numbers from units to tens.
Form 2: Math quizzes
– Read and analyze the problem: Determine the given data, the amount of increase or decrease and the requirements of the problem.
– Find a solution: Based on the key words of the problem such as finding “all”, “remaining” … and the requirements of the problem to determine the appropriate calculation.
– Presentation of the solution: Write the solution, calculation and answer to the problem.
– Check the solution of the problem and the results just found.
Form 3: Find the missing digit in the addition calculation.
– Perform addition from units to tens.
– The addition operation has three values: the first term, the second term, and the sum. If I know the value of two of those three values, I will mentally find the missing numeric value.
1.3. Solve textbook exercises page 5
Write the correct number in the blank (follow the pattern):
Perform the addition of two numbers in order from units to tens.
Set calculation and then sum (in the form), know:
a) The terms are 42 and 36
b) The terms are 53 and 22
c) The terms are 30 and 28
d) The terms are 9 and 20
Do the calculation according to the pattern.
– Set calculation: Write the digits in the same row and column together.
– Calculation: Add the digits from right to left.
A shop sells 12 bicycles in the morning and 20 in the afternoon. How many bicycles did the store sell in two sessions?
Morning sale: 12 bikes
Afternoon sale: 20 bikes
Full day sale: ….. bike?
To find the number of bicycles sold all day, we need to add the number of bicycles sold in the morning plus the number of bicycles sold in the afternoon.
Two times the shop sold all the bicycles:
12 + 20 = 32 (bike)
Answer: 32 bicycles.
1.4. Solve textbook exercises page 6
Perform addition of numbers from right to left.
50 + 10 + 20 =
60 + 20 + 10 =
40 + 10 + 10 =
50 + 30 =
60 + 30 =
40 + 20 =
Add up the digits of the tens place mentally and then add a 0 to the end of the result you just found.
50 + 10 + 20 = 80
60 + 20 + 10 = 90
40 + 10 + 10 = 60
50 + 30 = 80
60 + 30 = 90
40 + 20 = 60
Set the calculation and then sum, knowing the terms are:
a) 43 and 25; b) 20 and 68; c) 5 and 21
– Set the calculation: Write the calculation in a vertical row so that the digits in the same row and column are together.
– Calculation: Add the numbers in order from right to left.
In the library, there are 25 boys and 32 girls. How many students are in the library altogether?
Male students: 25 students
Female students: 32 students học
All of students?
To find all the students in the library, add the number of boys plus the number of girls.
The number of students in the library is:
25 + 32 = 57 (student)
Answer: 57 students.
Fill in the blanks with the correct number:
Repeat from right to left to find the missing number.