1. 27 + 33 + 67 = 27 + 100 () 2, 125 × 16 = 125 × 8 × 2 () 3, 134-75 + 25 = 134 - (75 + 25) () 4, multiply the first two 1、27+33+67=27+100 （ ） 2、125×16=125×8×2 （ ） 3、134-75+25=134-（75+25） （ ） 4. Multiply the first two numbers first, or multiply the second two numbers first, and the product remains the same. This is the law of combination of multiplication 5、1250÷（25×5）=1250÷25×5 （ ） 2、 Choose (put the serial number of the correct answer in brackets) (8 points) 1. 56 + 72 + 28 = 56 + (72 + 28) used () A. Additive commutative law B, additive associative law C, multiplicative associative law D, additive commutative law and associative law 2、25×（8+4）=（ ） A、25×8×25×4 B、25×8+25×4 C、25×4×8 D、25×8+4 3. 3 × 8 × 4 × 5 = (3 × 4) × (8 × 5) uses () A. Multiplication commutative law B, multiplication associative law C, multiplication distributive law D, multiplication commutative law and multiplication associative law 4、101×125= （ ） A、100×125+1 B、125×100+125 C、125×100×1 D、100×125×1×125 3、 Calculate as simple as possible (35 points) 355+260+140+245 102×99 2×125 645-180-245 382×101-382 4×60×50×8 35×8+35×6-4×35 4、 Practical questions. (14 points) 1. From the first quarter to the fourth quarter, xiongcheng market sold 269, 67, 331 and 233 refrigerators respectively. How many refrigerators did xiongcheng market sell in the whole year? 2. The heights of the six members in the third group are 128 cm, 136 cm, 140 cm, 132 cm, 124 cm and 127 cm respectively. What is their average height?

1. 27 + 33 + 67 = 27 + 100 () 2, 125 × 16 = 125 × 8 × 2 () 3, 134-75 + 25 = 134 - (75 + 25) () 4, multiply the first two 1、27+33+67=27+100 （ ） 2、125×16=125×8×2 （ ） 3、134-75+25=134-（75+25） （ ） 4. Multiply the first two numbers first, or multiply the second two numbers first, and the product remains the same. This is the law of combination of multiplication 5、1250÷（25×5）=1250÷25×5 （ ） 2、 Choose (put the serial number of the correct answer in brackets) (8 points) 1. 56 + 72 + 28 = 56 + (72 + 28) used () A. Additive commutative law B, additive associative law C, multiplicative associative law D, additive commutative law and associative law 2、25×（8+4）=（ ） A、25×8×25×4 B、25×8+25×4 C、25×4×8 D、25×8+4 3. 3 × 8 × 4 × 5 = (3 × 4) × (8 × 5) uses () A. Multiplication commutative law B, multiplication associative law C, multiplication distributive law D, multiplication commutative law and multiplication associative law 4、101×125= （ ） A、100×125+1 B、125×100+125 C、125×100×1 D、100×125×1×125 3、 Calculate as simple as possible (35 points) 355+260+140+245 102×99 2×125 645-180-245 382×101-382 4×60×50×8 35×8+35×6-4×35 4、 Practical questions. (14 points) 1. From the first quarter to the fourth quarter, xiongcheng market sold 269, 67, 331 and 233 refrigerators respectively. How many refrigerators did xiongcheng market sell in the whole year? 2. The heights of the six members in the third group are 128 cm, 136 cm, 140 cm, 132 cm, 124 cm and 127 cm respectively. What is their average height?

1、 1. 27 + 33 + 67 = 27 + 100 (pair)
2. 125 × 16 = 125 × 8 × 2 (pair)
3. 134-75 + 25 = 134 - (75 + 25) (wrong)
4. Multiply the first two numbers first, or multiply the second two numbers first, and the product does not change. This is the law of combination of multiplication
5. 1250 ／ (25 × 5) = 1250 ／ 25 × 5 (pair)
2、 1. 56 + 72 + 28 = 56 + (72 + 28) uses (B, the law of combination of addition)
2、25×（8+4）=（ 25×8+25×4 ）
3. 3 × 8 × 4 × 5 = (3 × 4) × (8 × 5) uses (multiplicative commutative law and associative law)
）
4、101×125= （125×100+125 ）
3、 355 + 260 + 140 + 245
=（355+245）+（260+140）
=600+400
=1000
102×99
=102×（100-1）
=102×100-1-2
=10200-102
=10198
2×125
=2×（100+25）
=2×100+2×25
200+50
=250
645-180-245
=645-245-180
=400-180
=220
382×101-382
=382×（101-1）
=382×100
=38200
4×60×50×8
=（4×50）×（60×8）
=200×480
=96000
35×8+35×6-4×35
=35 ×（8+6-4）
=35×10
=350
4、 1. 269 + 67 + 331 + 233 = (269 + 331) + (67 + 233) = 600 + 300 = 900 sets
2、（128+136+140+132+124+127）÷6
=787 △ 6 ≈ 131.17 cm