Practice 1
One tray holds 6 counters. Another holds 4 times as many. How many counters are in the other tray?
Answer and teaching response
24 · Four copies of six give twenty-four counters.
Use equal comparison units to separate multiplicative comparisons from additive differences and identify the unknown quantity.
Get the student and teacher materialsLearning goal: A learner can choose multiplication or division for a times-as-many comparison and explain why adding the multiplier answers a different question.
You will need: Paper, pencil and optional counters. Use fictional collections; no learner names or personal records are needed.
Lee has 5 counters. Sam has 3 times as many counters as Lee. How many counters does Sam have?
15 counters. One comparison unit is Lee's set of 5; Sam has three copies of that entire amount.
A learner might say: Three times as many as five means five plus three.
Ask whether the three counts individual extra counters or complete copies of the original group. Draw both situations and compare their totals.
Use the first three tasks for guided practice. Try the final task without help. Record a drawing or equation as well as the answer.
One tray holds 6 counters. Another holds 4 times as many. How many counters are in the other tray?
24 · Four copies of six give twenty-four counters.
One collection has 21 counters and another has 7. How many times as many counters are in the first collection?
3 · Divide twenty-one into groups of seven to count the comparison copies.
A collection of 32 counters is 4 times as large as a smaller collection. How many counters are in the smaller collection?
8 · The smaller collection is one of four equal comparison groups.
A red ribbon is 6 cm long. A blue ribbon is 5 times as long. Find the blue length in cm and explain why 11 cm would answer a different question.
30 · Five copies of six centimetres make thirty; eleven would be five centimetres more than six.
For a reference amount of 4, compare three times as many with three more. State both results and describe what the 3 counts.
Three times as many is 12, with the 3 counting copies of four. Three more is 7, with the 3 counting additional individual units.
Look for:
If the idea is not secure: Label each box with the reference amount and count copies before calculating the total.
If the learner is ready: Write three related equations for a comparison of 36 and 9: find the larger amount, the copy count and the smaller amount.
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