995
DESCRIPTION
621. 995. Rounding. Up or down?. Up to 1000. 132. Chris Clements. . Learning Objective:. . Rounding. Rounding is used to approximate or estimate. Rounding is used to approximate or estimate. Rounding is used to approximate or estimate. - PowerPoint PPT PresentationTRANSCRIPT
995 621
132Up to 1000 Chris Clements
Rounding
Up or down?
<date>
Learning Objective:
<Steps to success>
Rounding
Rounding is used to approximate or estimate.
Rounding is used to approximate or estimate.
Rounding is used to approximate or estimate.
Sometimes an exact number is not always required. See
the following examples;
Numbers can be rounded either up or down
Rounding The number of
people who went to see William and
Kate after they got married
could be rounded to the
nearest thousand (1000). The number of sandwiches
needed to be made for a party may be rounded to the
nearest ten (10).
Rounding
The number of nails in a box
may be rounded to the nearest
100.
The time it takes a car to get to a destination may berounded to the nearest
minute.
Step 1 in the steps to success
continued
1) Identify the units digit
Take a look at these number lines.
continued
If a number ends in a 5, 6, 7, 8 or 9
If a number ends in a 1, 2, 3 and 4
So 125, 126, 127, 128 and 129 round up
So 201, 202, 203 and 204 round down
Now for the next 2 steps to success.
Do you think you know them?
continued
2) Numbers that end with a 5, 6, 7, 8 or 9 round up
3) Numbers that end with a 1, 2, 3 or 4 round down
Can you see if these numbers need to be rounded up or down.
continued
Is it closerto 230 or 240?
ROUND DOWN!
Does it end in a1, 2, 3 or 4?
Is it closerto 380 or 390? ROUND UP!
Does it end in a5, 6, 7, 8 or 9?
231 232 233 234 235 236 237 238 239
381 382 383 384 385 386 387 388 389
continued
251 252 253 254 255 256 257 258 259
781 782 783 784 785 786 787 788 789
651 652 653 654 655 656 657 658 659
951 952 953 954 955 956 957 958 959
continued
Round up Round down
Do these numbers;
continued
When rounding up or down there are three main things to remember;
1) Identify the units digit. 2) If the units digit is a 1, 2, 3 or 4
we round down.3) If the units digit is a 5, 6, 7, 8, or
9 we round up.
Rounding up or down
Steps to success
Activity
<type here>
Plenary
Find the number closest to 160;151, 164, 166, 154
74, 83, 75 and 86
Find the number closest to 420;411, 426, 414, 415
Which of these numbers give 80 when rounded to the nearest 10?
415
164
Which of these numbers give 190 when rounded to the nearest 10?
191, 184, 186 and 193
75 and 83
191, 186 and 193