adding (hard)
what is 100 + 290
what is 390
what is 30 + 12
what is 42
what is 10 times 10
what is 20
what is 1000 times 1000
what is 100000
what is 100 times 900
what is 900000
what is 100 + 4500
what is 4600
what is 50 + 50
what is 100
what is 20 times 20
what is 40
what is 2000 times 2000
what is 4000000
what is 100 + 500
what is 600
what is 400 + 350
what is 750
what is 100 + 100
what is 200
what 40 times 40
what is 1600
what is 900 times 900
what is 810000
what is 40 times 40
what is 1600
what is 500 + 500
what is 1000
what is 50 + 50
what is 100
what is 60 times 60
what is 3600
what is 1000 times 2000
what is 2000000
what is 300 + 900
what is 1200
what is 1000 + 1000
what is 2000
what is 67 + 90
what is 157
what is 36 times 36
what is 1296
what is 200 times 400
what is 800
what is 900 times 500
what is 450000