Tiêu đề Y2 Maths 2015b - 2024 Week 17 Notes.pdf ✅

Year 2 Maths – 2015b Term 2 2024 – Week 9 Notes What is Rounding? Rounding means making a number simpler but keeping its value close to what it was. The mathematic sign that we use for rounding is , which means about the same as, or approximately, or around. It is NOT = which means “the same as” or “is equal to”. There are 2 rules of rounding: Rounding up or Rounding down. Rules for rounding numbers: Rule 1: If the digit following the rounding place is 0, 1, 2, 3, or 4, we round down. 24 20 Round down Rule 2: If the digit following the rounding place is 5, 6, 7, 8, or 9, we round up. 25 30 Round up
Let’s try 1c: Question 1: Round 73 to the nearest 10. Ask yourself what is 73 closer to? • Is it closer to 70 or 80? So 73 rounded to the nearest 10 is ________________. And to express it mathematically, we write 73 70 Round 37 to the nearest 10. Ask yourself what is 37 closer to? • Is it closer to 30 or 40 ? Use this number line to help you if you are still unsure: 30 37 40 • And how do we express it mathematically? ________________ What happens if the number is right in the middle, such 65? 60 65 70 Then we usually round the number up to the nearest Ten
65 70 And 85 when rounded to the nearest ten 85 ??? And 55 when rounded to the nearest ten 55 ??? Then what about 95 if it is rounded to the nearest Hundred? • Let 9 remain as it is as it is in the Tens place, don’t touch it yet! • Look at "5" in the Ones place: which is 5 or more, so increase the "9" by 1 to "10" - That is 10 tens. 95 rounded to the nearest hundred is 100. Or we could watch a video at home that will make it easier for you. https://www.youtube.com/watch?v=FGckJEouZIE Could you apply the same principle and round these numbers to the nearest 100? Question 1: Round 688 to the nearest hundred. What should we do with? You try it yourself this time! Step 1: Draw a hill, and a valley on the left and a valley on the right: 650 688 600 700
Step 2: Find the number in the Hundreds place (688), which is 6 and write in the left valley. There are 2 digits to follow after 6, so put 2 zeros after 6 which makes it 600. Step 3: Count by hundreds. And the next hundred is 700. Write 700 at the right valley. Step 4: Write the number in the middle of 600 and 700 which is 650 on top of the mountain. Always put a 5 next to the number and that’s how you know what goes in the middle. Step 5: Determine the place of 688 on your mountain. Step 6: Which way does the car go? Does it dive forward, or does it slide backwards? And the answer is 688 _____________. Follow the same steps. a. Round 2370 to the nearest 1000. 2500 2370 2000 3000