Q1: Estimate the product by rounding to the nearest tens:
Sol:
Round each number to the nearest tens: 128 rounds to 130
283 rounds to 280
Now, multiply the rounded numbers:
130 × 280 = 36400
Round each number to the nearest tens: 224 rounds to 220
314 rounds to 310
Now, multiply the rounded numbers:
220 × 310 = 68200
Round each number to the nearest tens: 168 rounds to 170
312 rounds to 310
Now, multiply the rounded numbers:
170 × 310 = 52700
Round each number to the nearest tens: 183 rounds to 180
249 rounds to 250
Now, multiply the rounded numbers:
180 × 250 = 45000
Q2: Multiply the following numbers: 652 × 152 = .....................
Sol: Q3: Multiply 487 by 300.
Sol:
Step 1: Multiply 487 by 3.
Step 2: Insert two zeros on the right of the product to get 1 ,46, 100.
Hence, 487 x 300 = 1 ,46, 100.
Q4: Multiply 231 by 4,000.
Sol: Step 1: Multiply 231 by 4.
Step 2: Insert three zeros on the right of the product at the end to get 9,24,000.
Hence, 231 x 4,000 = 9,24,000.
Q5: A bag contains 125 kg of rice. How much rice will 89 such bags have?
Sol: Amount of rice in 1 bag = 125 kg.
Amount of rice in 89 bags = 125 x 89 kg
Hence, 89 bags will contain 11 ,1 25 kg rice.
Q6: How many seconds are there in a day?
Sol: Number of hours in 1 day = 24
Number of minutes in 1 hour = 60
Number of seconds in 1 minute = 60The total number of seconds in 1 day = 24 x (60 x 60) = 24 x 3600
Q7: Multiply 1,369 by 90.
Sol: Step 1: Multiply 1 ,369 by 9.
Step 2: Insert one zero on the right of the product to get 1 ,23,210.
Hence, 1,369 x 90 = 1,23,210.
Q8: Multiply 153 by 800.
Sol:
Step 1: Multiply 153 by 8.
Step 2: Insert two zeros on the right of the product to get 1 ,22,400.
Hence, 153 x 800 = 1, 22,400.
Q9: Multiply 105 by 7,000.
Sol: Step 1 : Multiply 105 by 7.
Step 2 : Insert three zeros on the right of the product to get 7,35,000.
Hence, 105 x 7,000 = 7,35,000.
Q10: 45 students and 6 teachers went on a day trip by train. One ticket per student cost them Rs. 175 and one ticket per teacher cost them Rs. 275. How much money they must have spent on their round trip?
Sol:
The total cost for students (Ts) is given by the formula: T_{s}=S×C_{s}
And the total cost for teachers (T_{t}) is given by the formula: T_{t}=T×C_{t}
We can find the total cost (T_{total}) by adding the total cost for students and the total cost for teachers: T_{total}= T_{s}+T_{t}
Substitute the given values into the formulas: T_{s} = 45 × 175
and T_{t} = 6×275
T_{total }= T_{s }+ T_{t }= 7875 + 1650 = 9525
Therefore, the group must have spent Rs. 9525 on their round trip.
Q10: A bus travels a distance of 285 km every day. What distance will it travel in a year?
Sol: Distance travelled by the bus in one day = 285 km
There are 365 days in a year.
Distance travelled by the bus in 365 days = 285 km x 365
Hence, the bus will travel 1,04,025 km in a year
Q11: A laborer can pack 575 apples in one hour and every day he works for 8 hours. How many apples will he pack in the month of February?
Sol: Number of apples collected in 1 hour = 575
Number of hours for which he works in a day = 8
Total number of apples collected in 1 day = 575 x 8
Number of days in the month of February(considering non leap year) = 28
Therefore, total number of days = 575 x 8 x 28
Q12: Estimate the product of 325 and 18.
Sol: 325 → 300 (Rounding off to hundred's place)
18 → 20 (Rounding off to ten's place).
325 X 18 → 300 X 20 = 6,000.
Thus, estimated product is 6,000.
28 videos110 docs30 tests

1. What is multiplication? 
2. How do you multiply two numbers? 
3. Can you multiply any two numbers together? 
4. What is the result of multiplying a number by zero? 
5. How can multiplication be used in everyday life? 

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