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• • • • • • • • • • I colculotor j
• Go for 495! • • • • • • • •
IJ Try to get to 495 with these
• II Try again with these
b 533
c 900
a 876
What 1s the same about these start numbers?
a 212
b 778
c 343
What 1s the same about these start numbers?

D Follow the rules Ftnd out what happens
11 you start with these numbers
a 7 42 b 384 c 272 d 803 CHALLENGE
e 383 f 738 g 561 h 164
• Choose other 3-digit start numbers and try them.
• Sort these numbers and the others from questions [1Jj to [ij
by the number of goes you needed to get back to 495.

El Find out how many goes you need
to reach 495 with these start numbers • Try to find a rule which connects the start numbers in each set.
• Record your rules.
a 812 b 597 c 148
d 254 e 687 f 701

rn Challenge

Open: choosing different 3-digit numbers to try and then sorting these and
a, b, c, e, f, g, h need 1 go; d needs 4 goes.
the others from [I]-~ , according to the number of goes it takes to reach
4q5_

Rule: The number of goes depends on the difference between the highest
a 3 goes b 3 goes c 3 goes d 4 goes e 5 goes f 3 goes and lowest digit.

Difference between highest 1 2 3 4 5 6 7 8 q
and lowest digit
All these numbers need 5 goes to reach 4q5_
Number of goes 6 5 4 3 1 2 3 4 5

All these numbers need 6 goes to reach 4%, provided that a zero is
placed before qq to make a three-digit number. For example:
a) 221 - 122 = qq; qqo - (o)qq = aq 1 ; qa 1 - lBq = 7q2; qn - 21q = aq3; qa3 -
3aq = 5%; qs4 - 45q = 4q5_