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21. 99. Rounding. To the nearest 10. 12. 57. Chris Clements. <date>. Learning Objective:. <Learning Objective>. Rounding. Rounding is used to approximate or estimate. Numbers are usually rounded to the nearest 10, 100, 1000, 10 000, 100 000 or even a 1, 000 000.
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21 99 Rounding To the nearest 10 12 57 Chris Clements
<date> Learning Objective: <Learning Objective>
Rounding Rounding is used to approximate or estimate. Numbers are usually rounded to the nearest 10, 100, 1000, 10 000, 100 000 or even a 1, 000 000. Decimals can also be rounded, usually to the nearest tenth, hundredth, thousandth…
Rounding whole numbers Whole numbers (also called integers) are counting numbers e.g. 1, 2, 3, 4… Negative numbers are also whole numbers e.g. -1, -2, - 3… Decimals are not whole numbers e.g. 0.4, 7.4, 2.36, 7.32… Decimals are not whole numbers e.g. 0.4, 7.4, 2.36, 7.32… Fractions are not whole numbers e.g. ½ 2 ¾, 25 ¼ …
When rounding to the nearest 10 there are three main things to remember; • Identify the units digit. • If the units digit is a 1, 2, 3 or 4 we round down. • If the units digit is a 5, 6, 7, 8, or 9 we round up. • When rounding to the nearest 10 there are three main things to remember; • Identify the units digit. • If the units digit is a 1, 2, 3 or 4 we round down. • If the units digit is a 5, 6, 7, 8, or 9 we round up. Rounding to the nearest 10 Steps to success • When rounding to the nearest 10 there are three main things to remember; • Identify the units digit. • If the units digit is a 1, 2, 3 or 4 we round down. • If the units digit is a 5, 6, 7, 8, or 9 we round up. continued
continued Lets see how well you are doing. REMEMBER Step 1! • Identify the units digit. 7 5 7 2 2 2 8 7 2 8 9 . 1 5 8 1
continued Onto the next step. Can you remember it? 2) If the units digit is a 1, 2, 3 or 4 we round down. 12 10 20 2 1 1 2 0 round down 60 54 50 4 5 4 5 0 round down continued
continued Now for the final step. Can you remember it? 3) If the units digit is a 5, 6, 7, 8, or 9 we round up. 10 20 17 1 7 7 2 0 round up 40 50 45 4 5 5 5 0 round up continued
Lets have a go at these; 20 27 30 2 7 7 3 0 round up 70 71 80 7 1 1 round down 7 0 80 85 90 8 5 5 9 0 round up continued
40 43 50 4 3 3 round down 4 0 34 30 40 3 4 4 round down 3 0 40 48 50 4 8 8 5 0 round up 90 95 100 5 9 5 1 0 0 round up
Activity <type here>
Plenary 90 bricks (9packs of 10) At a builders yard bricks are sold in packs of ten. Jim wants 87 bricks to fix a broken wall. How many bricks must he buy? He would be 4 bricks short and will need to go back again! He would be 4 bricks short and will need to go back again! If Jim went to buy 14 more bricks, what would happen if he rounded down to 10 and bought one more pack? 360 Round 356 to nearest 10 What makes these more difficult? 2730 Round 2732 to nearest 10