To solve complex addition and subtraction problems involving

To solve complex addition and subtraction problems involving decimals using rounding to check my answer. Year 5 - Number (GDS) Lesson 3

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Recap from the last lesson… Look at the skills and then quickly check your understanding. Previously, we looked how we could use rounding to estimate answers to addition and subtraction problems that included money. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Learning check: You do…. Let’s quickly recap the rules of using column method when adding and subtracting. . . 1. 2. 3. For column method, if you add two digits and the answer is more than 10, you must regroup by placing the ones of the number in the answer and carrying over the one. You cannot subtract a smaller digit from a larger digit. So for column method, if you come across this, you must burrow a “ten” from the next digit and add it to the smaller digit so that it can be larger. The digit you burrowed should then have one taken away from it. When estimating answers always round the numbers in the equation before solving it. Remember we estimate to make calculations easier. QUESTIONS: Estimate and solve: 1. 67321 + 10214 2. 39024 - 2941 = 3. £ 402. 33 - £ 121. 22 = 4. £ 492. 49 + £ 802. 21 =

Answers QUESTIONS: Estimate and solve: 1. 67321 + 10214 = Estimate: 77000 Answer: 77535 2. 39024 - 2941 = Estimate: 36000 Answer: 36083 3. £ 402. 33 - £ 121. 22 = Estimate: £ 280 Answer: £ 281. 11 4. £ 492. 49 + £ 802. 21 = Estimate: £ 1290 £ 1294. 70 Answer: Did you get these correct? If not, watch these videos from the last lesson of estimating adding and subtracting questions that involved money. If you feel confident, carry on with the slides.

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Teacher Example… Fluency - estimating answers to addition and subtraction equations that include decimals. Teacher example questions: Estimate and solve the following equations: 1. 742. 38 - 382. 12 = 2. 1391. 31 + 3941. 31 = Have a look at the video to see how we can round and calculate equations that include decimals.

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Estimate the answer to the nearest hundred and then solve the following equations: 1. 2. 3. 4. 3832. 13 + 3829. 31 = 9832. 55 - 4961. 32 = 7061. 21 + 501. 11 = 448. 21 - 291. 92 = Learning check: You do…. Answers: 1. Estimate: 7600 Answer: 7661. 44 2. Estimate: 4800 Answer: 4871. 23 3. Estimate: 7600 Answer: 7562. 32 4. Estimate: 100 Answer: 156. 29

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Teacher Example… Application and reasoning questions. . . Application question: Elizabeth’s rectangular living room has a length of 832. 23 cm and a width of 1291. 87 cm. Estimate the perimeter of the entire room to the nearest whole number. Reasoning question: Sam thinks of two numbers that when added together would give an estimated answer of 5000 when rounded to the nearest whole number. He thinks the two numbers are 3480. 49 and 1519. 15. Are his numbers correct? Explain your answer. Watch the video to see how we can solve these problems.

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Learning check: You do…. Q 1 At the end of the month, Susan has to pay her bills. Her electricity bill is £ 892. 73, her water bill is £ 1331. 99 and council tax is £ 1899. Due to an error in the system, Susan is given a £ 943. 50 discount off her total. Estimate how much Susan has to pay to the nearest whole number. Q 2 James thinks of two numbers that when rounded to the nearest whole number it will give an estimated answer of 72000. His numbers are 64078. 04 and 5921. 67. Do you agree with his numbers? Explain your answer.

LI: To solve complex addition and subtraction problems involving decimals using rounding to check my answer. I can use my knowledge of rounding to make an estimate. I can use column method when adding or subtracting I can burrow/regroup when necessary to get my answer. Vocabulary Adding subtracting Altogether More than Left over How many more Column method Regrouping burrowing Estimating rounding Learning check: Answers: Q 1 At the end of the month Susan has to pay her bills. Her electricity bill is £ 892. 73, her water bill is £ 1331. 99 and council tax is £ 1899. Due to an error in the system, Susan is given a £ 943. 50 discount off her total. Estimate how much Susan has to pay to the nearest whole number. £ 893 + £ 1332 + £ 1890 - £ 944 = £ 3171 Q 2 James thinks of two numbers that when rounded to the nearest whole number it will give an estimated answer of 72000. His numbers are 64078. 04 and 5921. 67. Do you agree with his numbers? Explain your answer. No. The value 64078. 04 rounds to 64078 when rounded to the nearest whole number so it will be one off from the 72000.

Well done! Now complete the worksheet below on the google doc. You can either write the answers on the google doc, or write it out on paper and send a picture of your work to your teacher. https: //docs. google. com/document/d/1 p. Gq 7 rd. SEe. BPZ 8 o 0 Ykw. JISR 6 r 74 XWEX 9 pc. Cw. UVDUw. ESk/edit Remember to log onto maths whizz as well this week!