Operations with Integers
Multiplying with tokens
Find out how tokens can show multiplication of integers.
The token model handled addition and subtraction. Can it give meaning to MULTIPLICATION too, including multiplication by a negative number? It can, with one rule to remember: for every new operation, start with an EMPTY bag.
Begin with what you know. Put 2 positive tokens into the empty bag, and do that 4 times. How many positives are in the bag? Eight. So 4 × 2 = 8, and we can read the multiplication as 'place the multiplicand into the bag, multiplier times'.
Name the parts while they are in front of you: in 4 × 2, the 4 is the MULTIPLIER, the 2 is the MULTIPLICAND, and 8 is the PRODUCT.
Now the new case. What could 4 × (−2) mean? Read it the same way: place 2 NEGATIVES into an empty bag, 4 times.
Negatives are red tokens, so place 2 red tokens into the bag, 4 times. There are now 8 red tokens in the bag, which means −8.
So 4 × (−2) = −8 — and nothing new had to be assumed. The same reading of 'multiplier times, place the multiplicand' gave the answer.
Use it on more. 4 × (−6) means placing 6 negatives into the bag 4 times, giving 24 negatives: −24. And 9 × (−7) means placing 7 negatives 9 times, giving −63.
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