Is $4000$4000 a reasonable estimate for $42\times8$42×8?
Is $400$400 a reasonable estimate for $2002\div5$2002÷5?
Irene had $120$120 dolls and she gave $18$18 to her friend Charlie. Charlie said that Irene had $138$138 dolls left. Is Charlie's statement reasonable?
Maximilian thinks $3.5$3.5 kg of apples will cost about $\$9.25$$9.25. Is this a reasonable estimate?
Use a range of additive and simple multiplicative strategies with whole numbers, fractions, decimals, and percentages.