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ESTIMATING THE PRODUCT
We used red, blue and yellow ribbons
for the birthday party decoration.
Approximately what lenght of each
colour were needed? Calculate using
the data in the chart.
The product can be estimated by calculating with the rounded value of a factor.
(Calculating with) values rounded
to the nearest HUNDREDS:
(Calculating with) values rounded to the
nearest TENS:
158 \latex{ \times } 3 \latex{ \approx } 200 \latex{ \times } 3 =
179 \latex{ \times } 2 \latex{ \approx } 200 \latex{ \times } 2 =
142 \latex{ \times } 5 \latex{ \approx } 100 \latex{ \times } 5 =
142 \latex{ \times } 5 \latex{ \approx } 140 \latex{ \times } 5 =
179 \latex{ \times } 2 \latex{ \approx } 180 \latex{ \times } 2 =
158 \latex{ \times } 3 \latex{ \approx } 160 \latex{ \times } 3 =
Calculate the product exactly.
158 \latex{ \times } 3 =
179 \latex{ \times } 2 =
142 \latex{ \times } 5 =
Compare the estimate with the exact calculation.
red
blue
yellow
length of ribbons
number of ribbons
158 cm
179 cm
142 cm
5 pcs
2 pcs
3 pcs
{{exercise_number}}. Estimate the product with values rounded to the nearest hundreds and tens.
nearest hundreds
nearest tens
218 \latex{ \times } 3
467 \latex{ \times } 2
309 \latex{ \times } 3
174 \latex{ \times } 4
325 \latex{ \times } 2
200·3=600
220·3=660
{{exercise_number}}. Approximately how much did the children pay for the picture frames? Calculate with values rounded to the nearest tens.
Aaron: 4 small frames Don: 1 medium and 2 small frames
Helen: 2 large frames Kate: 1 large and 2 small frames
PICTURE FRAMES
small
medium
large
254
375
429
cent
cent
cent
{{exercise_number}}. Connect the matching amounts.
112 \latex{ \times } 5
317 \latex{ \times } 3
199 \latex{ \times } 4
236 \latex{ \times } 2
\latex{ \approx } 800
\latex{ \approx } 960
\latex{ \approx } 480
\latex{ \approx } 550
\latex{ \approx } 400
\latex{ \approx } 900
\latex{ \approx } 800
\latex{ \approx } 500