13 Ways to Multiply and Divide Maniratnam–The Cashier Maniratnam is the cashier of king Jayan. His job is to find out the salary of all the people who work for the king. This chart shows how muchsalaryeachpersongetsinaday. Person Salary in a day Minister — Rs 195 Horse rider — Rs 76 Cook — Rs 65 Maniratnam wanted to calculate the salary of the cook for the monthofJanuary.Hewrote— 60 5 60 × 30 5 × 30730 1800 150 60 × 1 5 × 11 60 5 Rupees1800 + 150 + 60 + 5 = Rs________ Maniratnam’s daughter Bela has learnt another method to multiply.ShewrotelikethisandshowedittoBhanu,herbrother. Akka, how did 65 We can multiply you do this? 65 with 31 in two× 31 steps. We know(65×1)65 31 is 30 + 1. So, (65×30) first multiply 65+ 1950 with 1 and then with 30. 170 b)If Soha’s heart beats 72 times in one minute, how many times does it beat in one hour? h Now find out how many times it beats in one day. h Count your own heart beats to find out how many times your heart beats in one week. c)Ababy elephant drinksaround12Lofmilk every day.Howmuchmilkwillit drinkin twoyears? d)Ababy blue whale drinks around 200Lof milkin one day. Just imagine how much milk that is! Find out in how many days your family would use 200 L milk. How much milk would the baby blue whale drink in eight months? Karunya — The Landlord Karunya bought three fields. D)Goingroundandround! 142857 142857 142857 142857 142857 × 1× 2× 3 × 4 × 5 Do you find a pattern in all these answers?Discussthiswithyourfriends. Division Dolma took a loan from a friendto buy a moped for Rs 9,588. She has to pay it back in equal amountseverymonthforsixmonths. h How much will she have to pay every month?Sheaskedherchildrentocalculate. Her daughter did it Her son started this way. thisway. Nowyoucompleteit. 500 + 500 + 500 + 90 + 8 1000 + 95886 9588–3000 6 –60006588 –3000 3588 –3000 588 –540 48 –48 5 Willbothofthemgetthesameanswer?Discuss. 179 How MuchPetrol? Isha has Rs 1000 with her. She wants to buy petrol. One litre of petrol costs Rs 47. How many litrescanshebuy? MoneywithIsha = Rs1000 Costof1litre = Rs47 Litresofpetrolshecanbuy=Rs1000÷Rs47=? Ishacanbuy______litresofpetrol. Findout If Isha comes to your city, how much petrol can she buy with the samemoney? Children'sDay Children are happy today. They are celebrating Children’s Day. Each child will be given 4 coloured pencils from school. The school has got 969 pencils. To find out how many children can getpencilstheteacherasksthemtodivide. Iru's Way Sreeni's Way 969 9694 100 + 4 200 + –400 – Complete Iru’s and Sreeni’s way of division. What is the answer youget? 181 Shivangididitbyashortcutway. I learnt it after a lot of practice. In this you have to remember many things. Shivangi's Way 9694 242 –8 16 –16 09 I know that I have to divide 969 with 4. But I first only look at 9. I put an arrow to remember to bring down 6. –08 1 Iru I remember to bring down 9 and divide by 4. Yes! This is the remainder. 1 pencil is left. Oh! I can't remember so many things. I will do it my way. 182 h Atankisfullof300Lof water.Howmuch waterwill be filled in 25 tanks? If 15 buckets can be filled with one tank of water, how many buckets in all can be filledwiththe waterin25 tanks? h There are 28 laddoos in1kg.How many laddoos will be there in 12 kg? If 16 laddoos can be packed in1box, how many boxes are needed to pack all these laddoos? h Thereare26roomsinaschool.Eachroomhas4 plants.Ifeachplantneeds2cupsof water,how much water do we need for all the plants?