Question

Daisy makes 43 postcards, while Su makes 36 postcards. Choose the abacus representing the total postcards they made.

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Say: Let’s count the total postcards and identify the abacus representing the total.

Steps:
$\bullet$ Daisy makes 43 postcards.
$\bullet$ 43 = 4 Tens and 3 Ones.
$\bullet$ Su makes 36 postcards.
$\bullet$ 36 = 3 Tens and 6 Ones.
$\bullet$ Add the Tens together – 4 Tens + 3 Tens = 7 Tens.
$\bullet$ Add the Ones together – 3 Ones + 6 Ones = 9 Ones.
$\bullet$ To represent 7 Tens, there must be 7 beads over “T” and to represent 9 Ones, there must be 9 beads over “O”.
$\bullet$ The abacus in Option C has 7 beads over “T” and 9 beads over “O”.
$\bullet$ Hence, Option C is the correct answer.

WB: If required, use the whiteboard to represent the number of postcards collected by each and the total postcards using abacus.


Q: From the options, are there any abacus representing the number of postcards made by each of them? Which are they?
A: Yes. Option B represents 43 and Option D represents 36.