Solution: The original formula =1413/2512 (is this the simplest? Don't! ! It can also be divided by 157 to become 9/ 16).
2. Write ratio:
(2) If one number is 4 and another number is 2 more than it, what is the ratio of these two numbers?
Solution: 4+2 = 6, then the ratio of these two numbers is 4: 6. (Is that correct? Don't write 4: 6, pay attention to simplification, 2: 3, there is a ratio of 3: 2. )
(3)A and B go in opposite directions from C and D respectively. The speed of A is 1.5m/s, and the speed of B is 0.7m/s. What is the speed ratio of A and B?
Solution: 1.5: 0.7 (correct? For simplicity, 1.5: 0.7 = 15: 7)
3. Elementary arithmetic: It should be noted here that multiplication and division are calculated first and then addition and subtraction, and parentheses are calculated first! !
(4)1+4 * 5/2-6 = 5 * 5/2-6 =12.5-6 = 6.5 (correct? Don't count 1+4, and pay attention to the order of elementary arithmetic. )
4. Simple operation: If the formula can be simplified first, simplify first and then calculate.
(5) Calculation: 2580+ 152-2826*480/5024
Solution: If dividing 2826*480 by 5024 is particularly troublesome and easy to make mistakes, then simplify it, 2826/5024 = 9/ 16 (see (1), then 2826 * 480/5024 = 270).
Then 2580+ 152-270 = 2462.
5. Unit conversion: It should be noted that different units should be converted into the same unit.
(6) There are 1 rectangles with length 15cm and width 1 decimeter. What is the circumference and area of this rectangle?
Solution: circumference = 2 * (15+ 1) = 32 cm.
Area = 15 * 1 = 15 cm2 (right)
1 decimeter =10cm, so the circumference = 2 * (15+10) = 50cm.
Area =15 *10 =150cm2.