足したり掛けて10の倍数になるものを探す・演習2

(1) 1 + 5 + 2 + 8 + 5 + 9

(2) 96 + 15 + 87 + 4 + 85 + 13

(3) 34 + 59 + 68 + 41 + 32 + 66

(4) 19 + 26 + 85 + 74 + 81 + 15

(5) 67 + 12 + 84 + 33 + 88 + 16

(6) 5 × 2 × 6 × 8

(7) 5 × 4 × 3 × 2

(8) 3 × 5 × 2 × 7

(9) 4 × 3 × 5 × 6

(10) 2 × 7 × 9 × 5

(1)

= (1 + 9 ) + ( 5 + 5 ) + ( 2 + 8 )

=30

(2)

= (96 + 4) + ( 15 + 85 ) + ( 87 + 13 )

=300

(3)

= ( 34 + 66 ) + ( 59 + 41 )

+ ( 68 + 32 )

=300

(4)

= ( 19 + 81 ) + ( 26 + 74 )

+ ( 85+ 15 )

=300

(5)

= ( 67 + 33 ) + ( 12 + 88 )

+ ( 84 + 16 )

=300

(6)

=(5・2)・6・8

=10・48

=480

(7)

=(5・2)・4・3

=10・12

=120

(8)

=3・(5・2)・7

=21・10

=210

(9)

=4・3・5・(2・3)

=4・3・(5・2)・3

=36・10

=360

(10)

=(2・5)・7・9

=10・63

=630