The heads are the same, and the tails are complementary (the sum of the tails is equal to 10): formula: after a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail.
The first multiplier is complementary, and the other multiplier has the same number: formula: after a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail.
Count eleven times eleven times: formula: head joint, head joint, tail to tail.
In the third grade of primary school, I want to add and subtract small trees, multiply two digits by two digits, and divide three digits by one digit to calculate aliasing. 20 lanes each. Reward 50 points. 1. Calculation
15.7+4.5+4.3 0.65+7 1.8+ 10.35+9.2
30-(5-0.07)-(0.8+2.24) 62.32+ 16.39+5.68+3.6 1+ 12
8+8.4+8.2+8.6+7.8 1070.6-6.52-73.48
Second, find the number in ()
( )+0.35=3. 1 ( )- 18.25= 13.48
73.5-( )=27.93 0.007+( )=2.4 1
Third, the text problem
1) A number is 12.0 1, and B number is 0.9 less than A number. What's the sum of number A and number B?
2) The sum of two numbers is 100, and the number A is 27.95. How much is the number b more than the number a?
3) What number is subtracted from 26.53 to get 14.9, and how to find this number?
4) 18.26 is 30.57 less than a number. What is the number?
Fourth, the application questions
1) The factory transported a batch of coal and used 45.75 tons, 5 tons less than the rest. How many tons of coal was there in the factory?
2) The ocean area on the earth's surface is about 36 10/00000 square meters, which is 2120000 square meters more than the land area. How many billion square meters is the whole earth?
3) Saw off a piece of wood for the first time at 1.28 m, and the second saw off was 0. 16 m longer than the first saw off. At this time, there is still 0.72 m left. How long is this piece of wood?
4) The first number is 3.67, the second number is 2.54 less than the first number, and the third number is 2.3 1 more than the second number. What is the third number?
The second volume of the third grade mathematics is multiplied by two digits 1. Write the number directly.
1 1×20 70×20 40×30 30×2 1 30× 13
60×20 40× 12 1 1×50 25× 10 12×40
2. Is the following calculation correct? The mistake has been corrected.
1 4 1 2 7 3
× 2 5 × 1 7 × 2 4
5 6 7 4 2 9 2
2 8 1 2 1 4 6
8 4 1 9 4 1 6 6 2
3. Use vertical calculation.
14×26= 8 1× 18= 94× 1 1= 45×34=
4. Practical application.
(1) A bus can take 48 people. How many people can sit on 28 such buses?
(2) The school uses 50 kilograms of rice at noon and 45 kilograms at night every day. How many Jin of rice have you used for two weeks in a row?
fill (up) a vacancy
The sum of 1, 2 1 14 is (); 32 times of 24 is ().
2. The product of14 times 63 is (); What is the sum of 16 45s? The simplest formula is (), and the result is ().
3. After calculating 37×62, Xiao Ming can use ()× () to check whether the calculation result is correct.
The product of 4, 52 and the least two digits is (); The product of the largest two digits and 18 is ().
5365 plus () is exactly 14 times of 75.
6. Master Wang makes 18 parts per hour on average, so how many parts does he make 14 hours? Fill in the appropriate numbers in the brackets.
1 8
× 1 4
7, 2 ............................................................................................................................................................................
1 8 ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
2, 5, 2 ........................................................................................................................................................................
7. If the oral calculation is 35× 19, you can first calculate 35×20= () and then subtract () 35.
8. A box of color film can take 36 photos. According to this calculation, 15 box of film can take at most () photos.
9, the average adult weight is about 65 kg, 15 adult weight is about () kg. If these people take the elevator with a load of 1 ton at one time, will it be overloaded? ( )。 (Fill in: No overload or overload)
Second, orally calculate the following questions
Can (1) be calculated correctly and quickly?
8×40 =43×0 = 100-40= 3× 190=
40×9 = 270×3= 150×6= 4×28=
(2) Do oral calculations first, and then memorize these oral answers.
25×4= 125×8= 25×6= 125×2=
250×4= 1250×8= 25×8= 125×4=
Three, column vertical calculation of the following problems (with # to check)
83×26= 33×66= 84×59= 26×47=
#54×25= # 2 1×44= # 66×77= # 19×36=
Fourth, ask questions about the text
What is the 3 1 and 36 times? 2. What is135 32?
Verb (abbreviation of verb) application problem
1. The average daily coal consumption of the factory is 5 1 ton. How many tons of coal were used in 42 days?
2. Preliminary investigation: The average lucky money of each student in my class is 85 yuan, so what is the lucky money of 53 students in my class?
3. Xinya stationery cabinet sells 18 boxes of pens a day, each box 12. How many pens are sold per * *?
Seven, thinking about the problem
1, observe the example and then calculate;
For example: 24× 1 1=240+24=264, 47×11= 470+47 = 517.
Calculate 35× 1 1=( )+( )= (), 78× 1 1 = () = ().
2. 30 teachers from Aimin Primary School led 14 class to visit Zhou Enlai Memorial Hall, with an average of 48 students in each class. The bus of the bus company has 700 seats. Are there enough seats in these cars? Agree |
77×62= 306×4=
89×23= 18.7+2.9=
48×50= 2 15×5=
78×47= 69×45=
How to write one digit plus two digits is one digit plus two digits in grade three.
For example, one digit is 9, one digit is 1 1, and the sum is (20).
1 1+9
=20
How to calculate the vertical calculation of double digits multiplied by double digits in the second volume of mathematics in the third grade;
1, the last bit is aligned.
2. Multiply the digits of the lower multiplier with the digits of the upper multiplier, and the digits of the product are aligned with the digits of the lower multiplier.
3. Multiply the ten digits of the multiplier below by the two digits above, and the digits of the product are aligned with the ten digits of the multiplier below.
4. Add the products calculated twice.
Simple algorithm:
1, the sum of single digits is equal to 10, and the multiplication of the same ten digits: the number of ten digits plus 1 multiplied by another ten digits drops, and the multiplied two digits drop, and the number formed by these dropped digits is the even number multiplied by these two digits.
2. The sum of ten digits is equal to 10. Multiplication with the same number of digits: two digits multiplied by one digit decrease, and one digit multiplied by one digit decrease. These numbers make up an even number multiplied by these two digits.
3. Multiplication algorithm of arbitrary two-digit numbers: the number is multiplied by the single digit mantissa, and the decimal digits are recorded; Add up the figures obtained by cross multiplication of the upper and lower digits, and the mantissa of the previous decimal digit drops, and record the decimal digit, and the number composed of all the dropped digits is the final number.
22
*33
-
66
66
-
726
The number of digits of the following number is multiplied by the number of digits of a number, and then multiplied by the number of digits of a number.
Hope to adopt
A simple way to multiply 99999 by a digit is to let this digit be n.
Then 99999xn = (10000-1) n =100000n-n.
Sometimes it's easier to multiply a number by two numbers to become two consecutive numbers. For example: 5× 42 = 5× 2× 21=10× 21= 210.
Find 600 oral math problems in the third year of the next semester (be sure to multiply two digits by two digits, divide three digits by one digit, Decimal addition and subtraction) 54x78 25x46 72x6512x89 65x56 36x19 54x20 36x7810x331x112x/. kloc-0/4x 14 15 15 16 32 X84 26x 36 45x 14 47x 35 48x 32 58x 32 10x 50 74x 32 54x 32 14 x32 36x 17 32X48 36x 65 438+00 738
65X25
Third grade math: two digits, the product must be four digits wrong. There are also three digits. For example, 10 * 10 equals 100.